MANAGEMENT SCIENCE informs Vol. 57, No. 5, May 2011, pp. 897–914 issn 0025-1909 eissn 1526-5501 11 5705 0897 ® doi 10.1287/mnsc.1110.1326 © 2011 INFORMS INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Retail Channel Structure Impact on Strategic Engineering Product Design Nathan Williams Shell Energy North America, Spokane, Washington 99201, nathan.n.williams@shell.com P. K. Kannan Robert H. Smith School of Business, University of Maryland, College Park, Maryland 20742, pkannan@rhsmith.umd.edu Shapour Azarm Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, azarm@umd.edu W e examine, in a strategic setting, the broad issue of how retail channel structures—retail monopoly versus retail duopoly—impact a manufacturer’s optimal new product design, both in terms of engineering design specifications as well as manufacturer and retailer profits. Our strategic framework enables manufacturers in specific contexts to anticipate the reactions of the retailers and competitive manufacturers to new designs in terms of the retail and wholesale pricing and to understand how different channel structures and channel strategies (such as an exclusive channel strategy) impact the engineering design of the new product, conditional on consumer preference distributions and competitor product attributes. Based on a simple numerical and a power tool design example, we illustrate how the insight from the framework translates to design guidelines; specifically, understanding which designs are optimal under differing channel structure conditions, and which design variables need precise targeting given their profit sensitivity. Key words: new product design; engineering design; research and development; retail channels; marketing; game theory; genetic algorithms; latent class models; structural models History: Received September 30, 2007; accepted December 22, 2010, by Christoph Loch, R&D and product development. Published online in Articles in Advance April 1, 2011. 1. Introduction methodologies that consider cross-disciplinary impact and synergies (Morgan et al. 2001). In the engineering design literature, the methodologies developed have been improvements in engineering design aspects and assume that the manufacturer or producer interacts directly with the consumer in the marketplace (e.g., Li and Azarm 2000, Wassenaar and Chen 2003, Luo et al. 2005, Besharati et al. 2006, Luo 2011). These approaches rely on the estimation of customer utility for high-level product attributes that are the result of engineering design decisions. These high-level product attributes are translated into market share and profit with implications focusing on competitive draw or market expansion using a discrete choice model and generally a cost model (e.g., Ramdas and Sawhney 2001). With the emerging dominance and clout of retailers (Cappo 2003), recent approaches have started examining and accounting for the impact of retail channels in manufacturers’ new product design in addition to customer preferences. For example, from an analytical viewpoint, a number of game theoretic frameworks have been developed to understand strategic interactions in retail environments The product development process has been defined as the transformation of a market opportunity into a product available for sale and involving disciplines of marketing, operations management, organizational management, and engineering design with each discipline focusing on critical decisions (Krishnan and Ulrich 2001). These critical product decisions are ultimately realized as product attributes and features that are important to the market. The realization that the decision for many of these attributes and features is made early in the design stage and cannot be changed significantly later in product development to enhance the marketability of the product or its economic success has led to cross-disciplinary approaches in many of these related fields (Ulrich and Eppinger 2004). To that end, many approaches have been developed in extant literature to collect and integrate customer preferences in the early stages of design, aiming to provide the manufacturer flexibility in designing products that are market focused. Some of these approaches focus on the information sharing and coordination aspects across disciplines (e.g., Terwiesch et al. 2002); others propose specific design 897 INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. 898 Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design (monopolies—Dewan et al. 2003; duopolies—Savin and Terwiesch 2005, Klastorin and Tsai 2004). From an empirical viewpoint, Luo et al. (2007) examined the issue of how manufacturers can design new products strategically in a specific retail monopoly setting in order to maximize manufacturer profits, and Shiau and Michalek (2009) examined vertical Nash structures with symmetric competition at the retail and manufacturer level. Williams et al. (2008) analyzed how manufacturers can increase the acceptance of their new products by a retail monopolist through a mix of design options and slotting allowances. In this paper, we examine, in a strategic setting, the important issue of how retail channel structures itself (retail monopoly versus retail duopoly) and the specific channel strategy (e.g., exclusive or nonexclusive) impact of a manufacturer’s optimal new product design, both in terms of engineering design specifications as well as manufacturer and retailer profits. Specifically, we propose a framework that enables manufacturers, in specific institutional settings and under certain market assumptions, to anticipate the reactions of the retailers and competitive manufacturers to new designs in terms of the retail and wholesale pricing under different structures and channel strategies. In such a setting, the framework allows the manufacturer to determine the quality (the specific attributes) of the new product that the retailer(s) would prefer most to carry in their assortment given the specific distribution of consumer preferences and competitive product attributes. Based on numerical examples, including an application to power tool design, we illustrate how the insight from the framework—the increased competition in duopoly/oligopoly retail settings allows manufacturers to target the design preferences of the more price sensitive consumer segments more profitably as compared to the retail monopoly case—translates to specific design guidelines. Collectively, our paper provides important insights and testable hypotheses into how the downstream channel structure and the exclusive/nonexclusive strategy followed by a manufacturer will shape the optimal design characteristics of a new product as well as manufacturer/retailer profits, as the following overview highlights. In evaluating a new product to carry in their assortment, retailers typically use revenue per square foot or revenue per shelf space as metrics (in addition to customer preferences). The inclusion of the new product has to lead to an increase in overall category profit. For example, Home Depot will only carry in their assortment the 5 out of 20 available drills that generate the greatest revenue for the drill category. Additionally, in the presence of retail competition, this assortment composition is particularly important in maximizing the retailer’s market share vis-à-vis Management Science 57(5), pp. 897–914, © 2011 INFORMS their competition. Given these considerations and the fact that the retailers’ shelf space is limited, manufacturers have to strategically consider the attributes and features of their product vis-à-vis the assortment (i.e., competing manufacturers’ product features and attributes) the retailers carry. This must all be done at the early design stage so as to maximize the chances of the new product being carried by one or more retailers and being successful in the market. In considering the powerful retailers and their interactions, and the competitive manufacturers’ products and their designs, a manufacturer cannot afford to take a “myopic” perspective in the design decisions by considering only its technical design and its impact on the customers. Given that engineering design decisions determine product cost and attribute positioning at the foundation of the development process, it is logical to conclude that engineering design decisions of a manufacturer are transmitted to competitors and retailers as strategies to which they are forced to counteract. For example, just as a manufacturer considers retailers’ assortment, profit criteria, and competitors’ existing products in designing a new product, other competitors may anticipate this strategy and make their own move to influence the retailers. They might, for example, reduce their wholesale prices to the retailers to make the retailer margins more attractive. Retailers, on the other hand, may also consider such dynamics in new product offerings and wholesale prices in making their own assortment decisions considering the extent of retail competition. Thus, “games” in the marketplace calls for the manufacturers to be “strategic” in their design decisions. This is a key assumption of our approach that has considerable support in practice (Montgomery et al. 2005). Using the strategic approach proposed in this paper, a designer would be able to develop a scenario that if a product is designed with engineering design variables x, which result in customer level product attributes y, then an equilibrium price vector P would appear in the retail environment as a result of strategic interactions by competing retailers and manufacturers. The retail price vector P determines the market shares m and manufacturer profitability of the design that the manufacturer wants to maximize. Thus, using our approach, a manufacturer is able to determine the optimal new product design under different structures characterizing the retail channel, specifically, how the optimal engineering design variables x and manufacturer and retailer profits vary under different channel structure scenarios. Additionally, in the case of retail duopoly structures, our strategic approach enables consideration of the specific channel strategy early in the design process to determine the optimal new product design. It Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 899 INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Management Science 57(5), pp. 897–914, © 2011 INFORMS is important to note that our approach is appropriate in specific institutional settings where the model assumptions we make are valid. In market settings that are different, our framework can be used as a heuristic to develop hypotheses that could be tested using other approaches. With respect to the extant literature in the product development area, our area of focus—downstream channel structure, strategies, and product design decisions—has seen limited research (see Krishnan and Ulrich 2001, Krishnan and Loch 2005). Whereas early work has focused on upstream channels in explaining product variety in the market as a function of supply chain structure (Randall and Ulrich 2001) and in exploring the impact of supply chain configuration/coordination in a manufacturer–retailer competitive setting on product design/product variety in the market (Subramanian and Kapuscinski 2002, Subramanian et al. 2008), only recently have Luo et al. (2007), Williams et al. (2008), and Shiau and Michalek (2009) incorporated downstream channel considerations in an empirical setting to determine optimal product designs. However, these papers consider the design issue either only in the retail monopoly setting or in an analytical setting. Our approach focuses on understanding (in addition to customer-facing attributes and price) the variations in engineering design attributes and, more importantly, physical feasibility along with related costs within multiple channel structures (retail monopoly versus retail duopoly—identical versus differentiated) and channel cooperation strategies (exclusive versus nonexclusive strategies). In addition, our approach provides insights into which design variables need to be right on target and where variations in design variables can be tolerated under different channel structures. In §2, we provide an overview of our proposed framework along with model assumptions and justifications. In §3, we discuss the numerical examples and analysis that provide an illustration of our methodology, along with the different cases and results. We highlight the managerial implications and the challenges in generalizing the approach in §4. We conclude in §5 by presenting the contributions, limitations, and extensions of our approach and directions for future work. 2. Market Structure and Proposed Framework The product market that we consider is one characterized by manufacturers reaching out to customers indirectly through a retail channel consisting of powerful retailers (monopoly or duopoly). The manufacturers differentiate themselves with strong brands in a mature market and compete with other man- Figure 1 Strategic Design Framework Marketing design considerations Customer product celection mi P1i P2i P2i P1i WA x? WB WC WD Strategic design considerations Retailer competition Manufacturer competition Engineering design considerations ufacturers for retail shelf space. When they introduce new products, they set wholesale prices for the retailers who choose to either carry the product or not carry the product. Retailers set their own retail prices, which along with the wholesale price is taken into account for the carry or carry-not decision. This product market is characteristic of many consumer durables that are engineered and marketed to customers through retailers (e.g., power tools, household appliances, electronics, etc.). The multilevel strategic design framework is shown in Figure 1 for a retailer duopoly (which can be simplified to the monopoly channel by removing one retailer) with four manufacturers and four consumer segments. Table 1 provides the nomenclature we use in presenting the multitiered design framework. The product design problem will be analyzed from the perspective of the manufacturer firm (i.e., the perspective of a product designer in the firm—bottom level in Figure 1) who is interested in maximizing profit and can be described as follows. In a competitive market of i products, manufacturer A (the focal manufacturer) designs a candidate product with engineering design variables x that must take into account the strategic response of other manufacturers. We assume that the other manufacturers B, C, and D have only the strategic move of altering their wholesale prices WB , WC , and WD , respectively. This is a standard assumption (Luo et al. 2007) because other responses in attributes are difficult to achieve in the short term. For manufacturers to set wholesale prices, they must know the effect on market share, which can only be determined after retailers set their retail prices (e.g., Pri = P1i P2i PRi ; middle level in Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 900 INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Table 1 Management Science 57(5), pp. 897–914, © 2011 INFORMS Nomenclature Engineering design variables (e.g., current, diameter, length, etc.) Customer level product attributesa (e.g., weight, amp rating, etc.) Intermediate level variables (attributes not evaluated by customers) Engineering constraints Product index for an n product assortment Production cost of the ith product ($)a Wholesale price ($) of the ith producta Utility for attribute j of product i in segment k a Total product utility for a product i in segment k a Market share of the ith product in segment k (%)a Market segment size (%) Overall market share of the ith product (%)a Market size (units) Retailer index for R retailers Retail price ($) of the ith producta of retailer r Profit of Retailer r on product i ($)a Profit of manufacturer on product i ($) a x y z gx ≤ b i = 1 n Ci Wi uijk Uik mik Sk mi N r = 1 R Pr i r i i Functions of engineering design variables. Figure 1). We assume that both retailers and manufacturers are fully informed about customer preferences (top level in Figure 1), which is a valid assumption in mature markets (e.g., Villas-Boas and Zhao 2005). The market provides feedback to the retailers’ actions in the form of product market shares mi . The retailers choose their retail prices to maximize profits in the monopoly case or to reach price equilibrium in the duopoly/oligopoly case. Considering the retail price responses at the retail level, manufacturers can determine equilibrium wholesale prices. Given price equilibrium at the two levels (manufacturer and retail levels) the manufacturer is able to determine the efficacy of any candidate design x. The focal manufacturer can, thus, perform a strategic scenario analysis with retail profits and manufacturer profits as outcomes given any design candidate. Thus, the framework provides a rich and realistic environment for evaluating engineering design decisions because it accounts for the power of retailers and the strategic responses available to competitors. We expand on the links between engineering design, strategy, and marketing in the next subsection. 2.1. From Product Design to Market Share Before discussing the strategic interactions in any design evaluation, we present the mapping process for turning engineering design x into product attributes y, which are then used to determine market share mi . This process is depicted in Figure 2 for a hand-held power tool—a right angle drill. We assume that market information—competition and their offerings—is already available, through shelf surveys of assortments at the retailers. In the short term, we assume that the product attributes (except price) of competitor products, y, are fixed (e.g., the weight of competitor product). Each power tool’s attributes in the assortment are recorded as the existing competitor’s product attributes that are critical to the positioning of any new design. Customer preference data can be in the form of survey data or choicebased conjoint data. The customer preference data is analyzed using finite mixture estimation techniques to identify distinct latent class segments to capture the heterogeneity in customer preferences.1 This latent class conjoint estimation along with the shelf survey allows our design approach to search for gaps in the competitive landscape that are weak in terms of competitive offerings as well as find customer segments whose preferences are currently underserved. The integration of this information with a bottom-up translation of engineering designs into customer relevant product attributes is presented in Figure 2. The design process starts with an instance of design variables x, which are then transformed to product attributes y for the focal manufacturer through appropriate engineering computations and determination of intermediate variables z, which are frequently used for constraints (see the bottom two blocks in Figure 2). For example, the weight of product is calculated from the density and volume of its constituent components. Similarly, power and torque of a product will be functions of gear ratios, current, and voltage. Engineering constraints such as gear stresses, heat flux, armature velocity, and others are calculated at this point to determine if the candidate design is feasible before proceeding to market share estimate determination. Design variables and engineering functions (constraints or attribute functions) need not be continuous as we will employ a genetic algorithm (Deb 2001) to find optimal designs. It is worth noting that the marketing and engineering should collaborate (e.g., Morgan et al. 2001) to determine which product attributes and intermediate variables are most relevant in investigating for optimization (i.e., they must matter to customers or affect the production cost). For example, marketing communicates to engineering that weight is one of the important evaluation criteria to customers and should be an output of the design model. Similarly, if engineering and manufacturing have determined that revolutions per minute (RPM) is an important driver of cost in the past because of higher stresses and heat dissipation requirements, it should be communicated to marketing for inclusion in the conjoint study in an appropriate way. Even if customers place little value on such attributes, this knowledge will be important to the overall design optimization because designers can 1 Alternatively, a hierarchical Bayes conjoint estimation can also be used to capture heterogeneity. Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 901 Management Science 57(5), pp. 897–914, © 2011 INFORMS Figure 2 Product Design to Market Share Compute market share (latent class model) Uik = j∈i ujk expUik i=1 expUik + Unc mik = n INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Conjoint analysis mi = Sk × mik k u ijk Customer preferences (u jk ) Table 3 Shelf survey Competitor attributes Table 2 Convert to attribute utilities uijk = f (y) y Engineering computations Total mass (kg) Attribute computations y = f (x) Mt = Ma + Ms + Other components Girth G (m) G = 2(Ro + 0.004 (m)) Amp rating (amps) I (amps) Intermediate computations z = f (x) Armature diameter lr (m) lr = 2(Ro – t – lgap ) Stator mass Ms = ((Ro)2 – (Ro – t)2) · L · s 2 Armature mass Ma = ( · lr )/(4 · L · s ) Density of steel s Constraint computations g(x) ≤ b Armature and stator wire turns Nc , Ns integers Length to diameter ratio L / Ro ≤ 5 Nc · I Armature heat flux Ks (A/m) Ks = · l ≤ 10,000 r Ns · I K = Stator heat flux Ks (A/m) s (l + t) ≤ 10,000 r x Right angle grinder design variables (x) Current I (amps) Armature turns Nc (no. of turns) Stator turns Ns (no. of turns) Stator outer radius R o (m) Pinion pitch diameter Dp (m) Switch type Gear ratio r Stator thickness t (m) Stack length L (m) Air gap lgap (m) Tool body Stator relax preconceived notions for minimum RPM values (a constraint) and possibly reduce production costs without affecting overall product performance and utility. Thus, an early concurrent consideration of all the relevant criteria (engineering design and customer preference) by the product development team gives a significant advantage in avoiding the costly mistake of performing customer studies that do not contain all of the relevant attributes that are cost or performance drivers in the engineering model (see Loch and Terwiesch 1998). Once product attribute variables y are determined from intermediate engineering design computations, one can estimate the utility of each attribute y (with a piecewise interpolation of utility values assigned to attribute levels, if needed) based on the conjoint analysis estimates for each segment by summing the util- Rotor Bevel gears ities ujk , in segment k, of all attributes j that appear in product i resulting in Uik = j∈i ujk (1) The same procedure is repeated for each of the n competing products in the assortment. We estimate the segment share of product i in segment k as follows while taking into account the utility of the no-choice (or no-purchase) option Unc : expUik expU ik + Unc i=1 mik = n (2) The total market share (%) of a given product i is computed by summing over the segment size Sk (%) estimated using the finite mixture estimation techniques Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 902 Management Science 57(5), pp. 897–914, © 2011 INFORMS (Sawtooth 2001) and the market share within each segment mik (%) as mi = Sk mik (3) INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. k Given that retailers have increasingly consolidated power and control of the retail channel (i.e., access to consumers), evaluating the manufacturer’s design in the context of the effect it has on retailer profit is an important consideration, even with our primary objective being to maximize the manufacturer profit. Clearly, if the manufacturer is concerned with a possibility of being denied shelf space by the retailer, he or she would prefer to select a design that is much more profitable for the retailer than the existing assortment it carries. At the same time the manufacturer’s profit and the retailer’s profit are competing objectives so a manufacturer would benefit from being able to choose from an optimal set of designs with respect to each of these objectives. The formulation presented in this paper is such an approach to setting the manufacturer’s design strategy given a specific channel structure. As such, in addition to maximizing manufacturer profit we add a constraint to our formulation where the manufacturer also wishes to increase retailer profitability so as to ensure market access. Thus, the focal manufacturer’s objective (when facing a monopolist retailer) can be stated as max i = mi Wi − Ci xi s.t. gx ≤ b n i=1 inew ≥ n i=1 iold (4) Ci mi = f x The focal manufacturer’s profit i is maximized by altering engineering design variables x so as to satisfy engineering constraints gx ≤ b, realizing that market share mi is largely a function of y and therefore x. In addition to focusing on optimizing retailer profit we constrain the design search space to only those designs that improve the retailer’s category profit (i.e., inew ≥ iold .2 Production costs Ci can be modeled as a function of the engineering design variables x or can be estimated from product attributes y, like those shown in Figure 2 (U.S. Department of Defense 1999, Scanlan 2002). We have chosen to use the latter approach in our application, which is based on historical prices of products in a category. The formulation presented above may appear simple until one consid2 This channel profit constraint is deterministic although a stochastic or “chance constrained” approach has been developed for a singleobjective model in previous work (Williams et al. 2008). However, they do not consider this in a strategic context, that is, they do not consider the (re-) actions of other manufacturers or retailers. ers that market share is also significantly dependent on retail price Pi (as shown in Figure 2), which is also dependent upon the wholesale price Wi . The prices Wi and Pi are not under the manufacturer’s control because of competitor manufacturer and retailer reactions, which require us to develop a more nuanced framework that endogenize price equilibrium models. An equilibrium framework that analytically captures the interactions of Figure 1 is presented in Figure 3 for both monopoly (one retailer) and duopoly (two retailers) channels with an oligopoly of manufacturers competing with the focal manufacturer. The framework incorporates the layers of strategic pricing moves available to competitors under the classical game theory assumptions (Osbourne and Rubinstein 1994), assuming that players are rational and fully informed of each other’s possible strategic moves (i.e., perfect information). 2.2. Equilibrium Framework The focal manufacturer (manufacturer A) develops a new product A in the assortment i = 1 n, which has engineering design variables x (bottom layer, Figure 3) with an objective to maximize profit. In the short term (one quarter to one year) the competing manufacturers will be unable to change product designs because of the manufacturing line and supply contract modifications that would be necessary. However, they can alter their wholesale prices and do so under the assumption that their competitors will attempt to make a “best response” to any Wi decision (manufacturer layer, Figure 3). The retailers also select retail prices Pri that will maximize their profit under a “best” response assumption from their competitive retailer (in the case of a duopoly retail channel) or simply maximize profit (in the case of the monopoly channel). The retail prices and product designs affect each consumer segment depending on its specific preference structure, which the finite mixture latent class model estimates based on the conjoint analysis. These determine the segment sizes and the market shares (top layer, Figure 3). The strategic aspects of retailers and manufacturers selecting retail and wholesale prices based on Nash equilibria makes the problem of optimizing product design computationally intensive. Following Luo et al. (2007), we solve the layered equilibrium conditions as a nested algorithm where the pricing level optimization is the selection of retail prices P using the Nash equilibrium of profit for retailers. The setting of wholesale prices is also based on the concept of Nash equilibrium. Simultaneously (with retail price setting), we minimize the sum of the squares of the first derivatives of manufacturer profit functions with respect to wholesale prices Wi to solve the manufacturer first-order conditions (FOC) in the middle layer of Figure 3. This structure creates a vertical Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 903 Management Science 57(5), pp. 897–914, © 2011 INFORMS Figure 3 Equilibrium Framework Monopoly channel Duopoly channel Market share analysis: MSA2 Market share analysis: MSA1 —For each product INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. —For each product expUi mik = N i=1 expUi mi = Sk · mik expU mrik = R n ri r=1 i=1 expUri mri = Sk · mrik k k mi P1i mri Pricing level: PL2 Pricing level: PL1 11 P11 12 P12 1 W1 2 W2 mi 11 P11 1 W1 1 W1 1n =0 P1n n =0 Wn ··· Wi mri x max i = mi Wi − Ci i=1 Wi x s.t. gx ≤ b n i=1 iold Nash equilibrium for the manufacturers and retailers in setting prices. The details of the optimization methodology are provided in the online appendix (provided in the e-companion),3 where we also provide proofs that optimal engineering design is dependent on the channel structure. i=1 3.1. Impact of Channel Structure on Engineering Design: A Simple Numerical Example Let us assume we focus on a single design variable x (say, product life expressed in number of years). 3 An electronic companion to this paper is available as part of the online version that can be found at http://mansci.journal.informs.org/. rinew ≥ n i=1 riold Ci mi = f x Consider the manufacturer profit maximization problem of Equation (4) determining the optimal xi of product i, with the overall market share mi being the sum of market shares from each retailer r, mri . Then Equation (4) without the retailer constraint can be rewritten as max i = Numerical Examples and Analyses In this section, we provide two numerical illustrations to highlight how channel structure impacts optimal engineering design. The first example involves a very simple design problem to highlight the intuition behind different optimal designs for different structures and how they are related to customer preferences. The second example is a power tool design problem based on some customer preferences and firm and market data. n ∀r Ci mi = f x 3. 2 W2 x s.t. gx ≤ b inew ≥ 2 W2 1n 0 P1n = 0 n ··· Wn n =0 Wn ··· max i = mi Wi − Ci x 12 P12 Engineering design level: EDL2 Engineering design level: EDL1 n Pri xi R r=1 mri Wi − Ci (5) s.t. gx ≤ b Ci mi = f x Expressing the market shares derived for product i from each retailer using a logit expression and the cost function to be a quadratic function of x with coefficient c and intercept C, the above maximization problem can be written (dropping the subscript i) as the sum of profits derived from each retailer r: max = x N R W −cx −12 +x−cexpbx −P/+U r=1 expbx −P/+U +Utot +Unc (6) where N is the total market size. The designer/ manufacturer’s margin is the difference in wholesale Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 904 Table 2 Management Science 57(5), pp. 897–914, © 2011 INFORMS Example Problem Settings Figure 4 Competitor specific parameters Focal product Competitor 6.5 5 6 6 INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Common parameters C N U (no choice) B a 1/3 1,000,000 units −1.1 Focal manufacturer profit U (segment 1) U a (segment 2) 18 16 14 12 10 8 6 Segment 1 (50%) Segment 2 (50%) 10 1/5 12 8/15 U does not contain x (quality) or price utility. price W and the quadratic cost function with coefficient c and intercept of C. Utility increases linearly in x at the rate of b and utility decreases linearly in retail price P at a rate of 1/. We consider one other competing product in the market place and between zero and three retailers so profits are summed across the index r as well as segments k, which is suppressed (see Equations (2) and (3)). The total utility of competing product in this case is represented by Utot , and Unc is the utility of the no-choice option. The competitor has a design of x = 9 and identical cost structure to the focal manufacturer (see Table 2). Even with such a simple problem, an infinite number of analysis scenarios are possible, so we focus on realistic problem parameters that were robust in converging to pricing equilibria as shown in Figure 3. We analyze four simple cases: (1) no retailer (i.e., the manufacturers sell directly to market); (2) monopolist retailer; (3) duopolist retailers; and (4) a three-member oligopoly of retailers. Prices for the competing manufacturer and the retailers are calculated using a nested optimization using FOC for retailers and manufacturers as shown in Figure 3. The no-retailer case is important because if one is to believe that channel structure is important then we should see a difference between optimal design without retailers and those taking into account retail pricing. The cases are exhaustively analyzed for design optimality by parameterizing x between 2 and 15. Our aim is to see how optimal design changes according to market structure and examine why that is so. One can see in Figure 4 that the optimal design varies markedly by virtue of the channel structure. The optimal design (i.e., product life, which is a measure of design quality) for the monopoly case xm∗ = 78 is significantly lower than the other three cases. From there the duopoly structure has the next lowest optimal design xd∗ = 84, followed by the three retailer oligopoly xo∗ = 10 and finally when retail competition is neglected we have the highest quality design 4 5 6 7 8 9 10 11 12 13 14 Design variable x Monopoly Duopoly Oligopoly No retailer ∗ xnr = 109. The difference between the monopoly case and the competitive retail case is the most striking and is largely explained by the equilibrium pricing as shown in Figure 5. Clearly, in the monopolist case, equilibrium retailer markup increases significantly as quality is increased and the monopolist retailer prices the products much higher in general (an average of $133 for all products and $103 for the optimal product). The higher monopolist markup and prices are anticipated (see, e.g., Andersen et al. 1992) because of lack of a strong nochoice option. In contrast, average and optimal retail prices for the duopoly across all retailers (average $120, optimal $89) and oligopoly ($118, $98) cases are much lower, which is also consistent with expectations as retail competition rises. In examining Equation (6), costs increase quadratically in quality (left side of numerator) and utility increases linearly in quality so one would expect a trade-off to exist. The design variable equilibrium for the monopoly is reached much quicker (lower) in the parametric study because the comparative utility with the no-choice option is reached much more quickly with the higher markup from the retailer. At this point, subsequent increases in quality add insufficient utility to overcome the subsequent increase in price Figure 5 Average Equilibrium Retailer Markup as a Function of Focal Design 45 Focal manufacturer profit a Channel Structure Effect on Optimal Design Monopoly Duopoly Oligopoly 40 35 30 25 20 15 4 6 8 10 Design variable x 12 14 Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design Management Science 57(5), pp. 897–914, © 2011 INFORMS Figure 6 Pricing Change with Respect to x –4 Focal manufacturer profit INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. –5 –6 xnr* –7 –8 –9 xm* –10 xd* Monopoly Duopoly Oligopoly No retailer –11 –12 –13 xo* –14 4 5 6 7 8 9 10 11 12 13 14 Design variable x and loss of utility. We can see this by analyzing the inner focal manufacturer component of Equation (6). If we assume wholesale margins (first parenthetical in numerator of Equation (6)) have reached an equilibrium, changes in profitability can only be accomplished by the focal manufacturer changing x in the second numerator parenthetical in Equation (6): x + Pr / + U . Let A = bx + Pr / + U ; the following identity should be true at equilibrium when a solution is focused largely on one segment: dA/dx = b − 1/dPr /dx = 0 if we take an economic interpretation that the gain in utility for quality should be equal to the loss of utility for cost at equilibrium. Thus, the design equilibrium for a given strategic case is realized when the utility coefficient b is equal to the change in price with respect to quality dPr /dx after being scaled by the price scaling factor . We numerically observe that each of the strategic cases converged to a slope similar to b for segment 2 (see Figure 6). The slope for the monopoly and duopoly cases (change in Pr / with respect to x) is nearly equal to 8/15 at the optimal design that equates to the second segment’s quality sensitivity (b). The monopolist case, not surprisingly, converges to a design/price equilibrium that equates to the second segment’s price elasticity where consumers are least price sensitive. The second segment is the least sensitive to price increases and yet places more value on design improvements by virtue of the coefficient and b, respectively (see Table 2). Clearly, the monopolist is less interested in increasing quality because maximal profits can be made off of the second segment with very little penetration into the first segment (less than 17%). The remainder of the cases also have low penetrations in segment 1 (relative to segment 2), which were 30%, 22%, and 19% for duopoly, oligopoly, and no-retailer, respectively. These cases converge to slopes of 0.5 to 0.7, which is closer to the b attribute of segment 2 than that of segment 1 as expected. This numerical study suggests that retail pricing in the monopolist case will have significant effects on optimal design. Specifically, the monopolist retailer 905 has incentive to select products to take advantage of its strategic position, so it forces the focal manufacturer to produce lower/medium quality and price it high enough to skim the market. As more retailers enter the market prices get more competitive. As the monopolist retailer relinquishes control to a duopoly/oligopoly, the focal manufacturer starts to focus on increasing quality to capture market share from the higher-quality competitor as the price utility of all products increases. As quality increases, the products with lower prices reach more of the lowend, price-sensitive consumers. It is also worth noting that as more retailers are added to the channel the difference between the no-retail and oligopoly structures start decreasing. So, if the number of retailers is very high (fragmented channel) then manufacturers can totally disregard the impact of retailers in their design as that impact will be very minimal (it is as if there were no retailers). The results we discuss in this example are consistent with the analytical result (in Online Appendix B) that product quality tends to be higher, given the preferences of the consumer segments, and prices decrease with retail competition. Additionally, optimal designs are shown to be dependent on channel structure as shown analytically in Online Appendix B. Somewhat specific to this numerical example (i.e., both consumer segments value higher quality) quality increases with retail competition, as a focal product design gets closer to consumer segment preferences given the underlying settings and assumptions (e.g., that costs are a function of design and utility is mildly increasing in quality for both segments). Costs as a function of production run volumes, and higher-order utility functions may yield different results but one can make the firm conclusion that monopoly and duopoly retail pricing can affect design significantly— retail competition tends to increase product qualities, lowers prices, and allow offerings to reach the more price-sensitive consumers—and so the market structure should be taken into consideration by the designers. If the number of segments increase, the larger of the more price-sensitive segments’ preferences will have a greater impact on the optimal design. It should also be noted that consistent with the numerical nature of the previous example, the observations are only locally valid though consistent with extant economic/game theoretic literature and the analytical results in Online Appendix B. These results are functions of many parameters (segment sizes, cost coefficient, price sensitivity, quality sensitivity of segments, and the utility of no choice, etc.) and so are valid within close vicinities of these parameter values and thus cannot be generalized when one or more parameters change significantly. Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 906 Table 3 Management Science 57(5), pp. 897–914, © 2011 INFORMS Example Assortment at a Retailer Table 4 Utility Estimates for Four Latent Segments INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Segment Tool Brand Amps Life (hrs) Switch Girth (in) Weight (lbs) A W 8.00 80 Paddle 2 6.00 B X 12.00 110 Trigger 4 16.00 C Y 6.00 150 Side 2 5.00 D Z 9.00 110 Side 2.5 6.00 3.2. A Power Tool Design Example In this section, we present a practical engineering design example using four cases of varying retail channel structures to show the effect of taking into account the channel’s competitive structure on optimal engineering design based on an actual productmarket. We consider four manufacturers (A–D) and two retailers (1 and 2) (see Table 3). The channel structure cases are as follows: Case 1: Retailer Monopoly/Manufacturer Oligopoly. In this case, given the one retailer, strategic interactions occur only at the manufacturer level in setting wholesale prices that impact the engineering optimization. This is the baseline case that extends the prior work in the retail monopoly setting (Luo et al. 2007) to include engineering design optimization. Case 2: Retailer Duopoly/Manufacturer Oligopoly— Identical Retailers. In this case, each retailer carries the same assortment and consumers across all segments are indifferent as to which retailer to buy from, so the retailers compete only on price. This case is more complex than Case 1 because it also has strategic interactions at the retailer level. The formulation for setting retailer prices takes into account wholesale prices as before but now is formulated as an equilibrium optimization where retail prices are adjusted to minimize the square of the first derivatives of the duopoly retailers’ profits with respect to price. Although somewhat unrealistic, such a case should demonstrate downward pressure on retail prices and therefore wholesale prices relative to the monopoly case. This will also serve as a baseline to examine Case 3 and Case 4 results. Case 3: Retailer Duopoly/Manufacturer Oligopoly— Differentiated Retailers. This case is more realistic because it accounts for the differentiated preference of consumers for the retailers themselves. For example, Lowe’s targets female customers with wider, brighter isles and a greater emphasis on decorating. A conjoint study can easily include samples where product i is offered at retailer r and then assess the value that consumers place on the “retailer attribute.” In Table 4 we show that three out of four customer segments prefer one retailer over the other. Case 4: Retailer Duopoly/Manufacturer Oligopoly— Exclusive Retailer Strategy. This models the case Share (%) Brand W X Y Z Price $60.00 Slope u/$ Amps 6.0 9.0 12.0 Life (hrs) 80.0 110.0 150.0 Switch type Paddle TopSlider SideSlider Trigger Girth Small (1.5 in) Large (4 in) Weight 16 lbs 9 lbs 6 lbs Retailer One Two 1 2 3 4 36.40 26.62 13.17 23.81 01 01 01 01 22 −24 −15 17 −05 02 08 −05 01 01 01 01 05 11 01 −16 238 −006 01 283 0001 −0045 005 212 0002 −0035 009 187 0001 −004 01 0001 13 01 −14 01 01 01 05 −14 10 01 01 01 −15 −07 21 006 01 01 −05 −24 28 01 01 02 −09 13 −04 01 01 01 −01 −05 06 01 00 01 −47 −58 105 008 003 004 08 07 −15 01 01 01 04 −10 24 −18 01 01 01 01 03 −07 −01 04 01 01 00 01 −33 −30 25 39 005 004 005 004 −07 04 06 −03 01 01 00 01 05 −05 01 01 07 −07 01 01 15 −15 003 003 24 −24 01 01 −23 05 18 00 01 01 08 12 −20 00 00 00 −15 05 10 002 001 004 15 05 −20 01 00 01 05 −05 01 01 07 −07 01 01 −15 15 005 005 14 −14 01 01 005 006 01 006 −02 −02 12 −08 01 01 01 01 where manufacturers and retailers seek exclusive channel relationships (Moner-Coloques 2006) as a means to secure access to market (manufacturer’s perspective) and as a means to differentiate an assortment for greater profits (retailer’s perspective). We model this arrangement in a manner similar to Case 2 except that the focal manufacturer decides to go to the market through only one of the two identical retailers as an exclusive retailer strategy. This approach where one retailer is allowed to fulfill all demand has been shown to theoretically improve profits for both parties in the exclusive channel (Tsay and Agrawal 2004). The retailer chosen for the exclusive relationship will carry the new product offered by the manufacturer as long as its profits improve relative to the original assortment just as in the previous cases. The competing retailer not chosen for exclusivity with our manufacturer simply offers the original assortment. We apply Cases 1–4 to a previously developed design problem. Although the channel structure of the case is characterized by a differentiated duopoly, we analyze an assumed monopoly structure (with the more dominant of the two retailers as the monopolist), an identical duopoly, and the possibility of the manufacturer going into an exclusive channel contract Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 907 Management Science 57(5), pp. 897–914, © 2011 INFORMS Figure 7 Optimization Formulations Monopoly Duopoly max i = mi Wi − Ci max i = mi Wi − Ci max INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. x Wi i=1 i s.t. gx ≤ b max x Wi n i=1 Ci mi = f x inew ≥ max i = mi Wi − Ci x Wi x Wi n Exclusive n i=1 iold 2 n r=1 i=1 x Wi max ri s.t. gx ≤ b x Wi ∀r n i=1 Ci mi = f x with one of the retailers. The monopoly case forms the baseline to examine the impact of duopoly, and the identical duopoly is used as a baseline to compare the exclusive channel contract. These comparisons provide better insights into how the channel structure impacts design decisions, which is quite useful for the focal manufacturer as the channel structures do vary across different categories of tool manufacturers. A detailed engineering design structure and conjoint data (Williams et al. 2008) were available for common small angle grinders and an ideal candidate application for the case studies as they are typically sold in a strong retailer channel environment. A brief shelf survey of the channel controlling retailers would reveal an assortment similar to that shown in Table 3. For the four strategic cases considered, our model replaces tool A with a new product when the channel constraint is met in Equation (4). The assortment is the same for the retailers under the monopolist and duopolist cases in that they carry the new product and products B–D. For the fourth (exclusive retailer channel) we assume that retailer 1 carries the new product and that the competing retailer carries the existing product (i.e., product A from Table 3). 3.2.1. Estimating Number of Segments and Market Shares. The latent class segmentation module (Sawtooth 2001) of the Sawtooth Software Market Research Tools (SMRT) was used to perform a conjoint analysis for small angle grinders (Figure 7) reanalyzing the customer response data from Williams et al. (2008) treating price as a continuous attribute and the other attributes as discrete levels. The results of the conjoint analysis are tabulated in Table 4. Each segment has an estimate of utility mean () and standard deviation (#) for several possible alternatives of product attributes. The utilities are normalized using Sawtooth Software. For the application we assume that prices are set by players (retailers and manufacturers) based upon the mean value for attribute utilities. A linear interpolation of utilities from Table 4 is used for any product attribute along with Equations (1)–(3) to determine the segment and market share of any given design. inew ≥ n i=1 iold n i=1 1inew s.t. gx ≤ b n i=1 1inew ≥ n i=1 1iold Ci mi = f x 3.2.2. Engineering Model. An engineering model is necessary to produce feasible designs that generate product attributes that are evaluated at the customer level on the basis of the finite mixture latent class model estimates. These attributes will impact production costs as well as the strategic pricing of any product. We employ a detailed engineering model that provides direct links from design variables to customer conjoint attributes in Table 4. The components that are the greatest drivers for tool cost are shown in Figure 2 with the associated engineering design variables at the bottom of the figure. One can see that the rotor and bevel gear assembly slip inside of the stator that is then encased in the plastic body of the tool. The engineering design variables shown are evaluated to ensure feasibility as well as calculate product attributes (weight and girth) prior to utility conversion and ultimately calculation of market share as explained in §2.1 (see Williams et al. 2008 for all computations; also included in the online appendix). Stator and armature mass make up a large component of the motor mass Mm presented in Figure 2 that is then used to compute the designs’ utility from Table 4 using piecewise linear interpolation. Like any engineering problem it is necessary to satisfy constraints to ensure that the product will operate safely under a variety of conditions as well as be durable and reliable. These are shown in detail in the online appendix, Table E1, and ensure that the design selection process does not produce motors that will exceed constraints such as heat flux limits or the recommended slenderness ratio L/Ro . These constraints are evaluated before any pricing algorithm is run as developed in §2.2. Thus, we are able to reject infeasible engineering designs prior to the computation cost of reaching wholesale and retail prices. Production cost is a critical component in our strategic framework because an increase in cost puts upward pressure on wholesale and retail prices for any competitor. We model cost Ci as a function of product attributes that takes the form presented in Equation (10): Ci = &0 + &1 I + &2 I · V /Mt + e (7) Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design where &1 and &2 are the multiple regression coefficients with estimates of 3.6160 and 0.1865, respectively; the estimate of intercept &0 is found to be −29.294; I is the current of the tool in amps; and IV /Mt is the power to weight ratio in watts/kg, where V is voltage and Mt is the total weight. For a detailed development of the multiple-regression cost model, see Williams et al. (2008). Finally, the example is implemented within our framework whereby engineering design variables (Figure 2) are optimized while taking into account engineering constraints and production costs (Equation (10)) all within the strategic pricing topology presented in Figure 3. 3.2.3. Analysis Details. We used Matlab’s Genetic Algorithm and Direct Search Toolbox (MathWorks 2007) to develop a multiobjective genetic algorithm to simultaneously optimize focal manufacturer profit (manufacturer A) and retailer profit. Although our focus (Equation (4)) is to maximize the focal manufacturer’s profit while ensuring that retailer makes at least as much profit as he was making with the existing assortment, an extension to finding the Pareto solutions for manufacturer and retailer profits helps to understand design impacts within a channel better, as we show subsequently. Additionally, one could argue that the increase in the retailer’s profitability above the prior assortment profit would strengthen the manufacturer’s case to obtain shelf space. Thus, we formulate the manufacturer’s decision as two objectives: (1) maximizing his own profit, and (2) maximizing the channel partner’s profit (monopolist, duopolist, or exclusive retailer). This can be described mathematically by adding the retailer profit maximization objective to the engineering design level (Figure 3). (In the retail duopoly, retail profits are the sum of the two retailers.) Three optimization formulations that we evaluate at the engineering design level are shown in Figure 7. A nondominated sorting algorithm (Deb 2001) is employed to find a Pareto frontier for each strategic situation (monopoly, duopoly with identical retailers, and duopoly with differing retailers, and the exclusive retailer). The inner optimizations for retail price setting and wholesale price setting are strictly quasiconcave for monopoly and duopoly price setting (see the proofs in Online Appendix B) and as such are amenable to gradient based optimizers such as Matlab’s fmincon (MathWorks 2007). The computational issues involved in our methodology are discussed at length in Online Appendix C. 3.3. Results of Numerical Analysis The results focus on manufacturer A’s design strategy in developing a new design to replace the existing product A design in the market under different channel structures. We assume that the competitor Management Science 57(5), pp. 897–914, © 2011 INFORMS products remain in the market with their existing attributes but possibly changing wholesale prices, which is taken into account in developing the new design scenarios using strategic analyses. Because our numerical results are a function of (a) the relative utilities of consumers in the different segments, (b) the competitive product attributes and positioning in the market, and (c) competitor actions, we graphically provide the impact of these interactions by considering changes in design attributes as functions manufacturer and retail profits under the different channel structures and strategies. 3.3.1. Impact of Channel Structures: Monopoly, Identical Duopoly, and Differentiated Duopoly. The optimal design solution set of each of the strategic cases presented in Figure 8 are unique and are a function of the specific channel structure. All designs have a high probability of acceptance by the retailers because they satisfy the profitability improvement constraint from Figure 7, but, of course, those designs that provide higher retailer profitability provide an extra incentive for the retailers to carry the product (i.e., designs M1, ID1, DD1). The Pareto frontier (rather than analyzing a single design) is interesting in that manufacturers can analyze a trade-off between retailer incentives and their own. Strategies can even be developed from this information. For example, under the monopolist setting the manufacturer might propose a $5 million slotting allowance to the retailer to carry M3 instead of M1. Clearly, the manufacturer is expected to be better off under that choice than designing M1. Similarly, the design ID3, although is Pareto optimal, is an exceedingly poor choice for the manufacturer if we do not consider the retailer profit as an objective. In this case the manufacturer can select design ID∗ with relatively little loss in profit but a significant improvement in retailer profitability. Figure 8 also provides those designs that provide significant profits to the manufacturer while Figure 8 Comparison of Strategic Case Results for Focal Tool 420 400 M1 Increasi M2 ng amp 380 Retailer profit ($M) INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. 908 360 rating M3 ID1 340 DD2 ID2 320 300 DD1 260 240 220 125 DD3 Increasi ng amp 280 rating Monopoly retailer Identical duopoly Differentiated duopoly 135 145 ID3 155 165 Manufacturer profit ($M) 175 185 Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Management Science 57(5), pp. 897–914, © 2011 INFORMS ensuring that the retailer profits are high (designs M2, ID2, and DD2). These designs can be considered as “optimal” designs under each channel structure and are included in the table in Online Appendix C. The monopoly Pareto frontier spans the lower profit regions for manufacturers—both duopoly cases have solutions acceptable to the retailers that have higher profits than the monopoly solution with the greatest manufacturer profit. In addition, monopoly retailer profits exceed profits of either of the duopoly cases, which is consistent with the extant literature (Anderson et al. 1992) given that the monopolist does not have competitive pressure to shift prices lower. In Figures 8–10 duopoly profits are the sum of the two retailers’ profits. The increased price competition in the two duopoly retailer cases (identical and differentiated) allows for the possibility of greater manufacturer profits. Retail prices are significantly lower for the duopoly cases as expected (Andersen et al. 1992; and as in the previous numerical example) which increases the overall market penetration and profitability for the focal manufacturer by reducing the number of consumers who do not participate in the market (choosing no-choice option) and focusing on the more price-sensitive consumers and their preferences. To reduce these retail prices for the duopoly cases the optimization feedback from the retailers suggests that lower production cost and lower wholesale prices are preferable (even though the best assortment fit lies in the high performance/high retail price strategy as evidenced by the monopoly results). The lower production cost has important implications for the optimal designs. Specifically, they drive down the current rating. This is precisely what we see in Figure 9, which shows that the duopoly case designs tend to be characterized by lower current rating and weights as compared to the monopoly case. For example, none of the competitor products (Table 3) can compare on amp rating to the monopoly designs that reach 14.5+ amps nor the extremely low performing solution at 4.5 amps (see Figure 9, bottom panels). In addition to a high current rating, the focal manufacturer has chosen to largely pursue designs in the 2.5 in to 3 in girth range and 10 to 14 lb range for the powerful monopolist models, which is significantly smaller in girth and lighter than the competing powerful product (product B) and larger/heavier than all of the rest of the competing products. However, these results are also easy to explain when one examines the customer preferences in Table 4. From Table 4 we can infer that segments 2 and 4, which together make up 50% of the market, prefer heavier and more powerful tools. They are also not as price sensitive as segment 1. Therefore, in the monopoly case, the retailer prefers to 909 carry a high performance, more expensive assortment of tools with higher margins and focus on the relatively price-insensitive and quality-sensitive segments to skim the market (the segments make up 50% of the market). Hence, the optimal design for the focal manufacturer tends to be the heavier and higher price tool. However, when the channel structure changes to duopoly and price competition starts to overwhelm the other attributes as competition forces prices lower, the more price-sensitive segment 1 (with a market size of 36%) suddenly becomes more important to the retailers competing for marker shares and profits as more consumers participate in the market moving away from the no-choice option lured by lower prices. Given this fact, the focal manufacturer starts to focus on designs that are lower in prices, lower in power (amperage), and lighter in weight (see Table 4) catering to the needs of the more price-sensitive segments. This is precisely what we observe in Figure 9, where the duopoly solutions tend to align more with the more price-sensitive segment 1 preferences. The insight that emerges from this analysis is similar to the one from the numerical analysis in §3.1— under the monopolist condition, the retailer targets the price-insensitive segment to make more profits— this results in higher prices than otherwise for the consumers targeted and depending on quality preferences for this segment and the location of competitive products, the segment may or may not get the quality they most prefer. Under duopoly with more price competition, the retailer has an incentive to target the more price-sensitive segments with products they prefer the most. In this case, it is the segment 1 preferences that determine the optimal design to a great extent. The plots in Figure 9 also show that the tool attributes affect the players (retailers or focal manufacturer) differently depending upon the strategic case. The most drastic example is the effect of increased current rating on the duopoly cases. Even minor increases in current appear to drive manufacturer profitability sharply lower. This is because higher values of current are farther away from the ideal values for segment 1 and also lead to higher manufacturing costs. Thus, increased cost causes the manufacturer to lose profits in the environment of stiff price competition. A weaker trend can be seen in the decreased manufacturer profits associated with heavier tools for the duopoly cases. The opposite is true for the monopoly case where the monopoly retailer is able to encourage the design of the tool that fits his or her assortment (heavier and more powerful) without regard to price competition. Just as importantly optimal profits of all parties are relatively insensitive to girth and some strategies are distinctly absent for design considerations. For example there are no large Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 910 420 175 Retailer profit ($M) Manufacturer profit ($M) Focal Tool Attribute Correlations with Manufacturer and Retailer Profit 165 155 145 135 125 370 320 170 220 8.5 10.5 14.5 12.5 8.5 10.5 Weight (lbm) 14.5 450 180 Retailer profit ($M) Manufacturer profit ($M) 12.5 Weight (lbm) 190 170 160 150 140 130 120 400 350 300 250 200 1.5 2.0 2.5 3.0 3.5 1.5 2.0 Girth (in) 2.5 3.0 3.5 Girth (in) 190 450 180 Retailer profit ($M) Manufacturer profit ($M) INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Figure 9 Management Science 57(5), pp. 897–914, © 2011 INFORMS 170 160 150 140 130 400 350 300 Monopoly retailer Identical duopoly 250 Differentiated duopoly 200 120 4.5 6.5 8.5 10.5 12.5 14.5 Current (A) girth tools (above three inches in diameter) and no tools that are simultaneously light with low amperage. All tools are at least medium in weight, which implies that under no circumstances is the increased cost of higher power to weight ratios sufficiently offset by increased utility for higher-power, lower-weight tools. (Table D1 in the online appendix provides the details of the designs shown in Figure 8 by selecting a design from each end of the strategic case Pareto frontiers and also the optimal for each strategic case.) The insights from these results are very instructive. Under a monopoly structure, retailer steers the new design to align with the segment that is least price sensitive and, in this case, the segment that prefers higher power and heavier tools. Under duopoly the assortments cover a wider spectrum of market preferences and the more price-sensitive segments. Thus, in our power tool design example, the optimal designs 4.5 6.5 8.5 10.5 12.5 14.5 Current (A) for the manufacturer under duopoly include light tools with low amperage as the manufacturer would be best served in designing cost reductions into the manufacturing process rather than increasing amperage (i.e., production cost is very important under these more price-sensitive environments). Given the distribution of customer preferences, overall manufacturer profits are extremely sensitive to current rating and somewhat sensitive to weight, and only smaller girth products were found acceptable. This provides designers specific targets for improvements in manufacturing and suggestions for successful designs. What if the manufacturer does not take into account the channel structure in such design decisions? Figure 10 provides the scenario of how designs developed under the assumption of a specific channel structure would fare if the retail structures were different. It also shows the performance of the opti- Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design 911 Management Science 57(5), pp. 897–914, © 2011 INFORMS Figure 10 Profit Performance of Designs Under Alternative Channel Structures Figure 11 200 450 350 300 250 200 150 Heavy tools, high amp rating, > 15 180 Retailer profit ($M) Retailer profit ($M) INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. 190 Monopoly retailer ID designs in monopolist objective NR-M No retailer in ID objective Identical duopoly Monopolist designs in ID objective No retailer in monopolist objective 400 Exclusive Relationship vs. Identical Duopoly NR-ID 100 ER2 ER1 170 ID2 160 ID1 150 Light tools, low amp rating, 5–7 140 130 50 120 0 0 20 40 60 80 100 120 140 160 180 200 Manufacturer profit ($M) 110 110 Exclusive retailer Identical duopoly 120 130 ID3 140 150 160 170 180 Manufacturer profit ($M) mal design solution derived under the no-retailer case (that is, disregarding the retailers and just considering the manufacturer competition) under a monopoly channel structure and duopoly channel structure. (The monopoly retailer and identical duopoly positions are the same as in Figure 8 to provide a basis for comparison.) It is clear that no-retailer solution (NR-M and NR-ID in Figure 10) is suboptimal under both scenarios. Only one design is presented for the NR situation because only a single optimal exists under the single-objective formulation. Not surprisingly, when the optimal identical duopoly (ID) designs are evaluated in the monopolist retailer objective function, they are suboptimal in comparison. This is largely due to a complete change in design focus for the manufacturer from segment 4 (dropping from 90% of its sales coming from segment 4 to less than 40%) to increasing segment 1 share from 25% to 50%. Segment 4 prefers high amperage designs whereas segment 1 prefers low and we noted that the monopoly designs tended to be high in amperage. The monopolist can afford to assign the focal manufacturer to this segment to extract the most profit because the remaining tools (B–D) fit the other segments relatively well and prices can be high all around because of the only competition being from the no-choice option, quite similar to the situation observed in the first numerical example. The monopolist retailer designs in the ID setting are even less successful as the high-amp, high-weight monopolist designs have too high of production costs to be competitive. The increased competition from two retailers (no longer just competition from no-choice) more than compensates for any added utility from the higher amperage and thus these designs are not selected for retention in the genetic algorithm solution set. This analysis further highlights the need to consider retail channel structure in design decisions. 3.3.2. Analysis of the Exclusive Case/Strategy. We analyze the exclusive retail channel strategy that is common in the power tool industry where, for example, Home Depot exclusively sells Husky hand tools and Ryobi power tools (Han Shih 2005). To set up the exclusive retail channel we selected one of the two retailers as a “channel partner” who has exclusive rights to carry the new tool (tool A) along with tools B–D. The remaining retailer or “competing retailer” in the subsequent figures carries the original assortment (tools B–E). Tool E is the design in place prior to optimization. We selected retailer 1 as a fixed choice for the exclusive relationship. The exclusive channel (Case 4) is compared to the most relevant example from the previous cases, duopoly with identical retailers (Case 2) in Figure 9. In Figure 11 we observe that the under the exclusive channel strategy the channel partner (retailer selected to carry the optimized tool) benefits greatly as the profits for the entire Pareto set dominate those of the nonexclusive case. In contrast, the manufacturer loses the possibility of achieving the highest profit. The manufacturer gives up $5–$40 million whereas the retail partner gains between $25 and $75 million in an exclusive relationship. If the manufacturer was already contemplating a design that maximizes retailer profit (left side of identical duopoly in Figure 11) and his chance of acceptance, the exclusive relationship may be worthwhile to pursue because it significantly increases retailer profits. This illustration explains the existence of exclusive retail relationships. Given that the retailer’s still have strategic dominance in this situation because of their control of market access, one can consider the exclusive offering as an incentive to a retailer to obtain shelf space similar to a slotting allowance. For a cash-strapped or riskaverse manufacturer the exclusive offering may be much more attractive than a slotting allowance. This risk is because of the high outflow of cash for a slotting allowance in the present period with no guarantee of sales volume. The profits of the model are INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. 912 Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design Management Science 57(5), pp. 897–914, © 2011 INFORMS still a prediction whereas a slotting allowance is an immediate deterministic outflow of cash. The characteristics of the designs under exclusive strategy are similar to those of the monopoly as the manufacturer’s new product competes against products B–D at retailer 1 and the entire prior assortment at retailer 2. Notice that segment 4 prefers to shop at retailer 1 (Table 4) and given that this segment also prefers heavier, more powerful tools it is not surprising that, under an exclusive channel agreement, retailer 1 would want a heavier, more powerful tool from the focal manufacturer so that the retailer can profit significantly from this segment. The exclusive case gives the opportunity for the focal retailer and manufacturer to offer heavy/powerful products much like the results from the monopoly case (details are presented in the online appendix). Thus, even though the duopoly case typically creates downward pressure on prices it is possible to position one’s design away from the low-performance/low-cost assortment that appeals to the price-sensitive segments and, specifically so when an exclusive relationship exists. The last two columns in Table D1 in the online appendix provide the details of the design under exclusive channel strategy. These designs tend to be heavy and powerful similar to the designs under the monopoly case. 4. Discussions and Managerial Implications The conclusions from the two examples are highly consistent with each other. Under monopoly retail, the retailer adds friction to the market. The retailer forces the manufacturers to target the price-insensitive segment to make more profits for themselves at the expense of the manufacturer and the consumers. The design, therefore, is dictated by to what extent the retailer wants to fulfill the preferences of the priceinsensitive segment given his profit motives. In the numerical example, this results in a high price, lower or medium quality product, given that a competing manufacturer already produces at the high end. In the power tool design example, the monopoly condition results in a design that caters to the price-insensitive segment—high amperage and heavier tools. With increasing competition at the retail level (duopoly and oligopoly), the market friction induced by the retailers decrease, and the optimal designs move in the direction to increase overall consumer utilities. The retail prices are lower because of competition, the more price-sensitive segments are targeted, and it is these segment preferences that determine the optimal design characteristics. In the numerical example, both segment utilities increase monotonically in quality and thus optimal designs under duopoly and oligopoly tend to be higher in the (single) quality dimension (thus increasing segment utilities), whereas being lower in retail prices. In the power tool design example, the utilities of the consumer segments do not increase monotonically in the multiple dimensions of quality, rather each segment tends to have its ideal designs consistent with the willingness to pay. Thus, in the power tool design example, the preferences of the more pricesensitive segments (which get targeted as the structure changes from monopoly to oligopoly) dictate the optimal designs—lower prices, low amperage, and lower weight products that increase the overall utilities for these segments, while being moderated by the location of the competitive products. Under increased competition, the consumers in both cases are able to get products that are closer to their ideal points. What our framework allows is to specifically determine the quality of the new product that the retailers would prefer most, under different channel structures, for targeting those consumer segments that maximize their profits—i.e., the specific attributes of the new product given a specific distribution of consumer preferences, competitive locations, and production costs. In the power tool design example, under the monopoly structure, the retailer sets an assortment that covers a portion of the customer preferences, albeit setting retail prices that are high, and forcing price-sensitive customers out of the market. Therefore, the focal manufacturer would be better off designing heavier and more powerful tools that align well with the retailer’s ideal assortment. On the other hand, the retail price pressure that is experienced in the duopoly case precludes any such (heavy/powerful) design by the manufacturer as the more price-sensitive customers with their preferences for lower performance tools come into play, unless the manufacturer decides on an exclusive channel agreement. Under the nonexclusive strategy, the optimal designs tend to be lighter and less powerful. Additionally, the results provide useful insights into the sensitivity of profits to the design attributes. Thus, manufacturer profits are very sensitive to current rating (even a small shift higher reduces profits significantly). On the other hand, weight is not as sensitive a variable, and only smaller girth products are found acceptable. This implies that from a design viewpoint, the manufacturer‘s target on current ratings has to be very focused with little room for variations, whereas the attribute girth tends to be small in all acceptable products. Understanding these degrees of freedom on the design attributes of the tool early on in the design process can lead to more acceptable and profitable designs. Similarly, if competitive pressures in the duopoly situation make the manufacturer very apprehensive of the eventual acceptance of their new product by Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. Management Science 57(5), pp. 897–914, © 2011 INFORMS either retailer, a risk-averse manufacturer would be able to make their offer significantly more attractive to a retailer with an exclusive channel contract with them. Although the manufacturer is limited to lower profits under such a contract, the exclusive relationship provides significant motivation for channel acceptance and may be preferable to choosing a higher retailer profit under the nonexclusive arrangement. The impact on the design is also quite different across these two situations as the exclusive strategy allows the retailer to act as a monopolist and thus the designs are closer to what we find under monopolistic conditions. 5. Conclusions The main contribution of our paper is (1) to show that the retail channel structure has a significant impact on the optimal design of a manufacturer, and (2) to provide a framework to take into account the retail channel structure and channel strategies in developing design guidelines appropriate for specific institutional settings and under certain market conditions. We illustrate our framework and its usefulness through numerical examples that show how the insights derived using the framework under those conditions translate to specific design guidelines. Specifically, it allows us to identify the attributes of the designs that are optimal under specific channel structure conditions, and the sensitivity of profits to different design variables. In such situations, the results using our framework are very useful to managers who are concerned about the acceptance of their new designs by the retail channel and getting shelf space. Our methodology provides a Pareto set of designs with varying manufacturer and retailer profits to choose from, under each channel structure scenario, so that manufacturers can mitigate the risk of shelf space denial. It is important to note that we have made many simplifying assumptions in the process for analytical and numerical tractability. Some assumptions such as retailer profit constraints (in Equation (4)) or that the costs are dependent on customer-facing attributes rather than underlying engineering design choices (Equation (7)) can be relaxed without impacting the general nature of the our results. But other assumptions are much more fundamental to the model. We assume that retailers and manufacturers are hyperrational and prefer equilibrium solutions in the short term. We also view the new product introduction as a single-period problem and also do not allow for other manufacturers to change any dimension other than price. In a multiperiod problem this is an obvious move by manufacturers. Thus, although our methodology may hold in markets that are characterized by 913 above market conditions (mature markets, for example, appliances and automobiles), it may not be appropriate for turbulent markets where players could have different motives (preemptive moves, price cuts, etc) or where competitors can react quickly with their own design changes. Thus, caution has to be exercised in deriving very general implications from the model and the results, given the heuristic nature of the framework application. It is also important to note that these results are conditional on the competitive positioning and the specific distribution of customer preferences in the market. Thus, what we provide is a framework that will allow managers to examine their situation numerically using the data on competitive positions and customer preferences characterizing their markets and within the ranges where the analytical results are valid. If the ranges are exceeded or if the functional form of demand as a function of product attributes and prices is much more complex, we can consider the results as only hypotheses, and thus the general implications of our results could be limited. One way to test such hypotheses would be to use new empirical industrial organization models (e.g., Sudhir 2001) to analyze historical data on new product introductions, prices, market shares, and retailer entries in specific markets to analyze the impact of retail structure over time on attributes and qualities of new products introduced. Such models can also be used to test for the strategic behaviors of the manufacturers and retailers (vertical Nash or Stackelberg’s leader–follower and deviations from these setups) (see Kadiyali et al. 2000). Such industry level analysis can provide insights into whether our framework can be applicable in specific institutional and industry settings. With regard to providing specific design recommendations to a focal manufacturer, we view our research as the first step. For future research, it would be useful to extend this methodology to take into account competitor strategies in other attributes (amperage, weight, advertising, etc.). This will no doubt be challenging because it involves extending the strategic analysis across multiple dimensions. Additionally, entire product lines face similar consideration along with competition from a store’s own brand, which may change the strategic landscape significantly and provide another avenue for extensions. It is obvious that such extensions will be very difficult to achieve within a game-theoretic framework, assuming hyperrational players. One way to make the results more general is to have more restrictive assumptions for a theoretical or acrossfirm treatment of such problems (Anderson et al. 1995, Kekre and Srinivasan 1990). Another approach to retain the practical usefulness of the model while Williams, Kannan, and Azarm: Retail Channel Structure Impact on Strategic Engineering Product Design INFORMS holds copyright to this article and distributed this copy as a courtesy to the author(s). Additional information, including rights and permission policies, is available at http://journals.informs.org/. 914 Management Science 57(5), pp. 897–914, © 2011 INFORMS considering more realistic scenarios is to use agentbased approaches to analyze competitive moves using Bayesian learning or dynamic games as alternative basis (see Hart and Mas-Collel 2000, Miller 2007). An agent-based approach can facilitate analysis of scenarios where players with different motives and objectives interact, allowing some of the hyperrationality assumptions and short-term reaction assumptions to be relaxed. 6. 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