What Drives Demand-Pull Innovation? An Empirical Investigation in the Computer Hardware Industry* Sali Li The University of Wisconsin–Milwaukee Lubar School of Business P. O. Box 742 Milwaukee, WI 53201 Phone: 414-229-6257 Fax: 414-229-5999 Email: li9@uwm.edu Richard L. Priem Texas Christian University Neeley School of Business TCU Box 298530 Fort Worth, Texas 76129 Phone: 817-257-7550 Fax: 817-257-7227 Email: r.priem@tcu.edu and LUISS Guido Carli University Department of Business and Management Viale Pola, 12 - 00198 Rome, Italy Email: rpriem@luiss.it Gianmario Verona Università Luigi Bocconi Institute of Technology and Innovation Department of Management and Technology Via Roentgen 1, 20136, Milan, Italy Phone: ++39‐02‐58366522 Fax: ++39‐02‐58366888 Email: gianmario.verona@unibocconi.it *Authors contributed equally. Please do not quote or cite without authors’ permission January 10, 2012 1 What Drives Demand-Pull Innovations? An Empirical Investigation in the Computer Hardware Industry ABSTRACT Despite extensive research in the fields of economics and the management of innovation over the past thirty years, the sources of demand-pull innovations have yet to be empirically validated. In this paper we pursue that empirical validation. We first review the literature on demand-pull innovation. Then, we argue that the likelihood of demand-pull innovations occurring depends upon: a firm’s relative focus on marketing versus R&D and a technology’s modularity, and further that these two factors interact as complements. We test these hypotheses using a sample of innovations patented in the computer hardware industry from 2001-2004. Based on our results, we discuss the importance of demand-pull as a contributor to innovation, and we link our findings to the broader debate comparing resource-focused versus demand-focused approaches to strategic management. 2 INTRODUCTION The seminal contributions of Joseph Schumpeter (1934; 1942) initiated research in the fields of economics and the management of technology aimed at increasing our understanding of innovation. This work is important because innovation is a critical issue for both scholars and practitioners. For scholars, a better understanding of innovation can help to explain competitive advantage in the increasingly dynamic markets that characterize modern competitive landscapes (Teece, Pisano & Shuen, 1997). For managers and entrepreneurs, an understanding of innovation can provide important guideposts for exploring new markets (March, 1991). A rich debate over “technology push” versus “demand pull” as mechanisms driving innovation has taken place in the literatures on the economics of technological change (e.g., Freeman, 1974; Mowery & Rosenberg, 1979; Dosi, 1982) and on technology-innovation management (e.g., Abernathy & Utterback, 1978; Tushman & Anderson, 1986; Christensen & Bower, 1996). Di Stefano, Gambardella and Verona’s (2011) review of empirical work in these fields confirms the persistent presence of the technology-push and demand-pull views in the literature. They also note, however, that compared to technology-push innovations relatively little attention has been paid to either the situations that increase the likelihood of demand-pull innovations or to the organizational factors that may facilitate them. Yet understanding the drivers of demand-pull innovation is increasingly important, in part because its role appears to be growing with the accelerating pace of technological change. For instance, advances in information and communication technologies have allowed firms to expand their knowledge bases more quickly by engaging users in their innovation processes (Chesbrough, 2003; Prahalad & Ramaswamy, 2004; von Hippel, 2005). This in turn has required 3 new ways of organizing for innovation in which the contribution of “pull” from the demand side has become pivotal (Arora, Fosfuri & Gambardella, 2001; Verona, Prandelli & Sawhney, 2006). This increasing importance of demand-pull innovation is reinforced by research highlighting the extreme challenges firms sometimes face when trying to convert technology-push innovations into successful products (Danneels, 2007). Concurrently, more attention now is being paid to users by the nascent demand-side approach to strategy (Adner & Snow, 2010; Priem, 2007; Ye, Priem & Alshwer 2012), which aims at better understanding the sources of value creation and competitive advantage sustainability from customers’ perspectives. Zander and Zander (2005), for example, argued that close customer relationships can help uncover information that is useful in guiding innovation. Faulkner and Runde (2009) provided a specific example when they explained how user innovations by hip-hop “DJs” reinvigorated the turntable industry. In sum, a deeper understanding of demand-pull innovation is fundamental to a broader and more accurate comprehension of value creation by firms in a dynamic marketplace. We contribute to developing this deeper understanding, first, by providing a method for empirically distinguishing between technology-push and demand-pull innovations and, second, by identifying key technology- and firm-level factors that contribute to demand-pull innovation. We explore two central research questions: Does technology modularity affect the likelihood of demand-pull innovation? And does the attention paid by a firm’s managers’ to technology relative to customers: (1) affect its production of technology-push versus demand-pull innovations, and (2) moderate the effects of technology modularity on the likelihood of demandpull innovation? Answers to these questions are likely to be helpful to scholars interested in factors contributing to innovation success, and to practitioners who wish to pursue opportunities available from customer-focused innovations. 4 THEORY DEVELOPMENT Studies in the economics of technological change have emphasized the fundamental roles of science and technology in the development of innovations across many economic sectors (e,g, Freeman, 1974; Rosenberg, 1982; Pavitt, 1984). Within industries, technology evolves along trajectories that often are punctuated by paradigm changes due to scientific advances (Dosi, 1982). This view of science and technology as drivers of innovation has come to be recognized as the “technology-push” approach to innovation, wherein entrepreneurs and firms develop marketable products primarily thanks to scientific discoveries. Although demand is seen as useful in this view for understanding how innovations could be marketed successfully, it historically has been viewed as more of a selection force rather than a generating force that spurs innovation (Di Stefano et al., 2011). In their classic review of demand pull and technology push, for example, Mowery and Rosenberg (1979) argued that, given the interrelated nature of the curves of demand and supply, it is impossible to distinguish any pull of demand from the dominant push of technology which typically generates innovation in most industries. Despite this dominant interpretation, pioneering work by scholars in the late Sixties highlighted a more generative role for demand. Schmookler (1966), for example, showed that fluctuations in investments in multiple U.S. industries were influenced more by external events such as upswings in demand than by inventive activity itself. Meyers and Marquis evaluated 567 successful technological innovations and concluded that “recognition of demand is a more frequent factor in innovation than recognition of technical potential” (1969: 60). In another study of successful innovations, Langrish et al. (1972) distinguished innovations triggered by customer needs from those originating in the firm itself. And von Hippel’s (1976) study of innovations in scientific instruments determined that innovative labor could be classified as either that of firms 5 providing engineering and manufacturing functions, or that of motivated users who are capable of innovating. Even scientists such as the famous robotics innovator Joseph Engelberger (1982), have noted that a recognized need, relevant technology, and financial support are critical elements for innovation. Overall, these studies confirm the importance of user demand – not simply as a selective force, but also as a generative force that spurs innovations. Following the lead of these early contributions, we distinguish between technology-push and demand-pull innovations as follows: Technology-push innovations are mainly the product of building upon science and technology, independent of specific customer or market needs. Demand-pull innovations are mainly the product of direct attempts to satisfy specific market needs. That is, if an innovation is primarily the result of scientific development, then it can be considered a technology-push innovation. If an innovation instead results from explicit or latent demand by a market segment, then it can be considered a demand-pull innovation. These distinctions between technology-push and demandpull innovations are matters of degree, however. Our use of the term “demand-pull” applies to innovations that integrate consumer needs and that are more focused on the commercialization aspects of technology advancement; any given innovation may be more (or less) technology push, or more (or less) demand pull, along a continuum. We do not mean to suggest that all innovations can be divided neatly into these two categories. Strategic Attention Focus and Demand-Pull Innovation Organizational context can influence innovators’ behaviors and, thereby, the types of innovation achieved. For instance, Tellis, Prabhu and Chandy (2009) showed that corporate culture can play a preeminent role in producing radical innovations, and similarly Ernst and Vitt (2002) found that key inventors change their invention patterns if an acquisition results in a 6 change in corporate culture. Wu, Levitas, and Priem (2005) determined that the job tenures of U.S. biotechnology companies’ CEOs influence their firms’ innovative outputs. These studies among others suggest that the “direction” of strategic attention paid by a firm’s managers can affect the overall orientation of the firm’s innovations. Following Ocasio, we define strategic attention as the “noticing, interpreting, and focusing of time and effort” (1997: 188). We next examine the focus of a firm’s strategic attention, as managers’ allocate scarce attention resources to marketing versus R&D, and the effects of this strategic attention focus on the likelihood of demand-pull innovations. The resource allocation of a firm reflects where its managers’ attention is focused and affects the firm’s culture and activities (Ocasio, 1997). As a firm focuses employee attention within or across different functions (Gifford 1998), “a discipline-dominant culture (such as a marketing or engineering culture) can impact the final outcome of the [innovation] process by attracting, motivating, and holding talented people from specific disciplinary fields (LeonardBarton, 1992)” (Verona, 1999: 173). Thus, from an attention-based view, firm strategic action is an outcome of how firms channel and distribute limited attention resources. As a firm increases attention to marketing activities relative to R&D activities, for example, a greater emphasis will be given to how to satisfy customer demands. Accordingly, a strategic attention focus on marketing will direct employees’ (including inventors and engineers) attention toward types of innovation that can better satisfy heterogeneous customer demands (Verona, 1999). On the other hand, as a firm decreases attention to marketing activities relative to R&D activities, a greater emphasis will be given to refining details of the firm’s existing technology. Accordingly, this strategic attention focus will direct employees’ attention toward innovations based on technological interdependence, and as inventors increase the depth of technology-based search 7 and exploration the breadth of external search for new knowledge and for market-based solutions will narrow. Thus: Hypothesis 1: The likelihood of demand-pull innovation increases as the strategic attention focus of a firm’s managers places a great emphasis on marketing activities relative to R&D activities. Technology Modularity and Demand-Pull Innovation Technology evolution is characterized by discontinuities that initiate periods of experimentation followed by convergence upon a dominant design. Anderson and Tushman (1990) argued that after each technology discontinuity there occurs an era of ferment followed by an era of incremental change. The delimiting event between these two eras is the emergence of a dominant design. Henderson and Clark (1990), for example, have demonstrated that firms tend to focus on fundamental architectural innovations before a dominant design emerges, but tend to focus on component innovations after the field converges on a dominant design. During an era of ferment, firms face substantial pressures to develop the next dominant design (Tushman & Anderson, 1986; Abernathy & Utterback, 1978), and the associated uncertainty makes it especially difficult to anticipate market needs. Managers and inventors therefore tend to focus more attention their own technology and on developing technological design superiority, so their design can become dominant. Once a dominant design is established, however, the era of incremental change begins and firms’ inventors and managers focus on incremental improvements to the dominant design that will make it more useful for customers. The critical innovation task becomes effectively commercializing the dominant design through incremental innovations incorporating customers’ increasingly heterogeneous demands. Modular product architecture standardizes the means through which product components interface. This in turn makes incremental innovations, via component replacements and 8 reconfigurations, easier for technology companies. Technology modularity thereby “facilitates ‘modular innovation’ (Henderson & Clark 1990): innovation in product components that does not significantly affect the design of other components. This kind of innovation allows firms to produce families of products based on the same overall product architecture, thereby helping them to address heterogeneity in customer demand (e.g., Langlois & Robertson 1992)” (Argyres & Bigelow, 2010: 842). In eras of incremental yet rapid innovation (Garud & Kumaraswamy, 1995; Galunic & Eisenhardt 2001), modularity allows more configuration alternatives from a given set of inputs, which in turn allows technology companies to better address the changing needs of increasingly heterogeneous segments of market demand following a dominant design (Schilling, 2000). Because modular innovation helps firms to more directly target customer needs, increasing heterogeneity of demand in a technological field spurs companies toward innovations that enhance inter- and intra-firm product modularity (Argyres & Bigelow, 2010; Schilling, 2000). Surprisingly, modular innovation may be especially likely among competitors following a much-demanded, “breakthrough” dominant design such as the Model T in automobiles (Argyris, Bigelow & Nickerson, 2011). The fundamental advantage of more modular systems over more technologically interdependent ones in fast-changing industries facing heterogeneous demand segments is exemplified by the mini-computer industry during the 1980s. Those companies with more modular product architectures, such as Digital Equipment Corporation, Data General and Hewlett Packard, responded to consumers’ needs for acrossbrand mini-computer and mainframe communications networks and distributed data-processing relatively quickly through flexible, modular innovations. Other mini-computer companies such as Wang Laboratories and Prime Computers, however, focused innovation instead on improving efficiencies in their proprietary, integrated systems. Due in part to the resulting inflexibility and 9 therefore inability to respond to customers’ needs, these firms eventually faded as competitors in mini-computer hardware (Schilling, 2000). Thus, modularity – i.e., increasing the possible configurations achievable from a set of inputs – makes it possible to better exploit customer preference heterogeneities. In order to respond to increasing market pressures from heterogeneous segments of demand, firms tend to further uncouple product components through finer specialization and more modular innovations (Schilling, 2000). This in turn fosters loose coupling of a firm's learning processes at the levels of product components and architectures (Sanchez & Mahoney, 1996), and enables firms to coordinate loosely coupled networks of suppliers and customers by acting as system integrators, thereby benefiting from both integration and specialization (Brusoni, Prencipe & Pavitt, 2001). Particularly important is the insight that the potential for division of innovative labor extends to technology users; i.e., in loosely coupled modular networks the locus of innovation may be spread across producers and users (Arora & Gambardella, 1994). On the other hand, during periods of ferment the benefits of adopting modular innovation are scant, in part because the market has yet to provide the clear signal of consumer preferences represented by a dominant design (Argyres et al., 2011). In such contexts innovations with high interdependency are more likely, but such innovations tend to occur through different processes (Baldwin & Clark, 2000; Fleming & Sorenson, 2001). Innovations that are high in technological interdependence are more difficult because they require that innovators delve more deeply into a technology’s details to understand of how components interact (Fleming & Sorenson, 2001). The process of building upon interdependencies redirects innovators’ cognitive and social resources toward technological priors and nuances (i.e., technology push), rather than toward exploring new ways of recombination to address customer needs (i.e., demand pull). Thus, although 10 interdependent innovations may be more difficult for competitors to imitate, they also are more difficult to achieve and, later, to build upon or modify. In sum, when technology firms face incremental eras with changing and heterogeneous segments of demand they seek flexibility and move toward modular innovations that allow component recombination in ways that better match the demand heterogeneity in the marketplace. These modular innovations are likely to be driven by consumers and, therefore, will tend to be demand pull. When technology firms face eras of ferment without strong demand signals from a dominant design, on the other hand, innovations built upon interdependencies with their own prior, proprietary technologies are likely. Such innovations are likely to be technology driven and, therefore, will be technology push. Thus: Hypothesis 2: The likelihood of demand-pull innovation increases with the degree of modularity in a technological field. Complementary Effects of Strategic Attention Focus and Technology Modularity The previous arguments leading to H1 explained why the strategic attention focus of a firm’s managers may influence the likelihood of demand-pull innovations by the firm, but they do not address the potential complementary effects that strategic decision focus might have on the relationship of technology modularity to the likelihood of demand-pull innovation that was proposed in H2. We discuss this issue next, building theory supporting complementary, interactive effects of managers’ strategic attention focus and technology modularity on the likelihood of demand pull. As Siggelkow has noted, “Two activities interact as complements if the marginal benefit of each activity increases in the level of the other activity” (2002: 901). Ocasio’s principle of situated attention “provides a link between how individuals think and decide in any particular organizational situation, and how the organization and its environment shape the situations that individuals find themselves in” (1997: 191). This principle suggests that a firm’s strategic 11 attention focus may complement the firm’s technology modularity, as follows. A marketingbased strategic attention focus is most pertinent and useful during eras of incremental yet rapid change when segments of demand with heterogeneous needs are becoming clearer in the marketplace. Because demand-pull innovations are most appropriate in such contexts, the efficacy of technology modularity will be increased by a firm-wide strategic attention focus on marketing that emphasizes the consumer needs. Moreover, the marketing-based strategic attention focus in turn will be legitimized and reinforced for employees by the need for modular innovation. In sum, the efficacy of technology modularity will be increased by firm-wide attention focus on customers, and the efficacy of a firm-wide attention focus on customers will be increased by technology modularity. Thus, there is a high likelihood that these factors will interact as complements, with increases in each together contributing to the likelihood of demand-pull innovations beyond their individual, main-effect contributions. The dual effects – main and interactive – of a firm’s strategic attention focus indicate that strategic attention focus can be classified as a “quasi-moderator” of the relationship between technology modularity and likelihood of demand-pull innovation. A quasi-moderator is a specification variable that is related to the predictor or criterion variables and that also affects the relationship between the predictor and criterion (Sharma, Durand, & Gur-Arie, 1981; Prescott 1986). In our case strategic attention focus is related to the demand-pull innovation criterion, and strategic attention focus also moderates the relationship between technology modularity and the criterion. In sum, we have argued that a firm’s strategic attention focus interacts with the previously described effect of technology modularity on demand-pull innovation, such that the effect of technology modularity on the likelihood of demand-pull innovation will be greater with increasing strategic attention focus on marketing relative to R&D. Thus, 12 Hypothesis 3: As a firm’s strategic attention focus on marketing versus R&D increases, a unit increase in technology modularity will have an increasing effect on the likelihood of demand-pull innovation. METHODS We test our hypotheses using sample firms from the U.S. computer hardware industry between 2000 and 2004. We chose this high-technology industry because computer firms need to bridge technology and customer demand in the innovation process (Randall et al., 2007), and innovations in this industry are well documented through firms’ patenting activities. Our computer hardware industry sample included SICs 3571, 3572, 3575, 3577 and 3578. We utilized the Compustat dataset and the USPTO patent dataset to construct our sample. We first selected all US computer hardware firms with R&D and advertising expenditure variables available in Compustat for the 5 year period of 2000-2004. During this process we eliminated foreign firms (i.e., ADRs) because our focus is on patents filed in the USPTO system. We then traced the remaining computer firms’ patenting activities using the NBER dataset and USPTO. In particular, we used the match indexes (PDPCOHDR and DYNASS) developed by the NBER led by Bronwyn Hall to merge the patent data with Compustat data. The PDPCOHDR index provides an accurate match between patent assignee name and Compustat’s GOVKEY, and DYNASS helps track the change of patent ownership in a given period of time (Bessen, 2009). This approach led to a total of 8828 patents from 74 U.S. computer hardware firms. During the 2000-2004 period 19 firms in our sample changed assignee numbers due to ownership structure changes. Nine of those firms terminated their business, but 10 changed to a new assignee number. We consistently tracked the patent activities of these 10 firms by matching their new and old assignee numbers. Dependent variable 13 Demand-pull innovation. We used the description found in each patent’s abstract to code the degree to which that patent reflects market pull versus technology push. A patent abstract provides important information on the essence of a patented technology. Patent abstracts have been used previously in technology research to identify the nature of a patented technology. Brusoni, Prencipe and Pavitt (2002), for example, used patent abstracts to code whether a patent represents an architecture or a component innovation. We took a number of steps when coding to ensure the validity of this measure. First, we consulted two industry experts, each of whom has multiple patents in the computer hardware industry and extensive experience with patenting. We explained our definitions of technology-push and demand-pull innovation in detail to each expert. We also used Randall et al.’s (2007) specific examples as a “roadmap” for ensuring agreement on the technological dimensions and user needs in the computer industry. After the experts agreed on the definitions of technology-push and demand-pull innovation, we selected 10 computer hardware patents, each of which was developed by one of these experts, and asked them to code the degree of demand pull for each patent on a Likert scale ranging from 1 (“purely technology push”) to 7 (“purely demand pull”) based on an initial coding scheme we developed. After discussion with the inventors, we refined the coding scheme for patents. The refined scale included: 1. Pure theory or method oriented; 2. Pure technology (such as chemical materials); 3. Technology that can be used in product, indirectly related to customer product, or technology breakthrough for certain specialty; 4. Technology that can be used in product that is directly related to customer product; 5. Technology that can be directly used by customer through a product or service provided by the company; 6. Technology that can be directly used by customer; 7. Innovation or technique created by customers or created purely based on customers’ 14 interests. In the appendix, we show examples of patent abstracts in each category to demonstrate coding the different levels of demand pull. Second, we hired two independent coders, each of whom have electronic engineering degrees and who had 18 and 7 years of professional experience at the time of our study. We explained the constructs of demand-pull and technology-push innovation to these coders, and then asked them to independently score the 10 patent abstracts that had been coded by the patent inventors along the 1-7 Likert scale of demand pull. If they arrived at the same score as did the patent inventors, we discussed their reasoning further to confirm their rationale. If they gave a different score than did the patent inventors, we discussed the differences and explained why the patent inventor coded that patent differently. Third, we then asked each coder to independently code another set of 100 patent abstracts, and compared the two coder’s results to ensure consistency. Thereafter, the coders independently coded all of the remaining patents. Overall, there was an initial 68 percent agreement between our independent coders, and Cohen’s kappa was .77, which is above the satisfactory level of .70 that was determined based on first 100 patents coded. When there were disagreements in the two coders’ ratings, they later discussed and resolved the disagreements, and their consensus was used in the analyses. Independent Variables Strategic attention focus. This construct was measured as the ratio of marketing expenses over R&D expenses. Prior research (Durand, 2003) has used the firm’s relative expenditures related to marketing and R&D to reflect a firm’s strategic attention focus. As noted by Ocasio (1997), a firm’s strategic attention focus reflects how the organization distributes and allocates critical resources. Technology modularity. Following Fleming and Sorenson (2001) and Sorenson, Rivkin, 15 and Fleming (2006), we measured technology modularity by calculating the “readiness” with which a patent’s technology subclasses can be recombined with other technology subclasses: n Technology modularity of patent j= ∑ E i/Count of subclasses on patent j where Ei denotes the easiness of recombination of subclass i, measured as the ratio of the count of subclasses previously combined with subclass i over the count of previous patents in subclass, and n is the count of subclasses on patent j. In this measure, technology subclasses serve as proxies for the technology elements that constitute the patented innovation. Although a patent’s subclasses may not always perfectly correspond to physical components of a patent, they are the defining, building blocks of the knowledge that comprises the patented innovation. The face validity of this measure has been validated via a survey of inventors (Fleming & Sorenson, 2004; Sorenson, Rivkin & Fleming, 2006). Patent class and subclass data were drawn from the Patent Network Dataverse by Lai et al. (2011). To derive the measure of easiness of recombination for a given subclass, we first counted all the prior patents containing the particular subclass from 1990 to 1999 as the denominator. We then counted of the number of different subclasses that have been combined with the particular subclass on previous patents as the numerator. Lastly, we calculated the average of the ease of recombination scores for a given patent to derive the measure of technology modularity. The basic intuition behind this measure is that if a patent’s subclasses can be easily “mixed and matched” with a variety of other subclasses, then the patent receives a high value of technology modularity. If, on the other hand, a patent’s subclasses have only been combined with a small set of other subclasses, which implies that the patent’s subclasses are interdependent upon each other and therefore its modularity is low. 16 Control Variables We controlled for the potential effects of knowledge searching by including a patent’s self-citations and basic science linkages in our analyses. Patent citation information provides valuable data concerning the flow of information to a firm from external sources (Griliches, 1990). Self-citation ratio is measured by the number of self-citations relative to the total number of prior citations in a four-year period. A higher number of self-citation indicates a higher level of embeddedness of the focal patent in the prior patents in the company (Hoetker & Agarwal, 2007). An important source of knowledge that patent inventors rely on is scientific publications. The more inventions incorporate recent scientific discoveries that are linked to basic science, the more citations a firm will list on its patents (Narin, Noma, & Perry, 1987; Bierly & Chakrabarti, 1996). Therefore, we followed prior research (e.g., Meyer, 2000; Harhoff, et al., 2003) by using the number of non-patent references in a patent as a proxy for the patent’s science linkage1. We also controlled for those firm characteristics that may affect innovation. Firm age was used as a proxy for the length of the firm’s patenting experience, because firms with longer patenting histories are more likely to build inertia and become less responsive to market needs. We calculated firm age as the difference between year t and the first year a firm appeared in the Compustat database. Also, firms with a rich stock of patents are likely to have a broader knowledge base and better capabilities from which inventors can draw. We therefore measured a firm’s patent size as the number of patents filed by the inventor’s firm from year t-3 to t. We also controlled for firm ROS in year t. 1 Not all non-patent references are from scientific journals – some are from industry journals and firm publications. This issue has been studied in detail by Schmoch (1993). As noted by Harhoff, et al (2003), however, most nonpatent references are from scientific journals, and it is very difficult to directly identify the number of explicit links to the scientific literature. We therefore used non-patent literature as a proxy for a patent’s science linkage and expect, despite the measurement issues, because non-patent literature references likely have explanatory power in science-based industries such as the computer industry. 17 We also controlled for the potential effect of alliance formation on innovation. Prior research has noted that alliances can affect the pattern of a firm’s innovation (Mowery, Oxley & Silverman, 1996; 1998). We followed Lavie and Rosenkopf (2006) by using alliance types to code the extent to which an alliance is functionally explorative. Using SDC data, we coded a categorical indicator of whether each alliance involved a knowledge-generating R&D agreement (coded 1); an agreement based on existing knowledge, involving joint marketing and service, OEM/VAR, licensing, production, or supply (0); or a combination of R&D and other agreements (0.5). The alliances’ functional exploration was assessed as the average value of the alliance type indicator across all alliances formed by firm i in year t-1. Values ranged from 0 to 1, where a high value indicates the exploration nature of a firm’s alliance portfolio, while a low value indicated the exploitation nature of a firm’s alliance portfolio. More emphasis on exploration alliances may be associated with technology-push innovation, while more emphasis on exploitation alliances may be associated with demand-pull innovation. Finally, we controlled for industry segment, technology category, and year effects. There are five major industry segments in the computer industry. We therefore included industry dummies for the following four industry segments: electronic computer (SIC 3571), computer storage devices (SIC 3572), computer communications equipment (SIC 3576), computer peripheral equipment (SIC 3577), with calculating and accounting machines (SIC 3578) as the base. Since there may be a systematic pattern of demand pull across patent technology classes, we included a control variable of patent technology category. But given the fact that our sample represents 188 unique technology classes, which is too large to serve as controls, we used the NBER-classification developed by Hall, Jaffe, and Trajtenberg (2001) to control the different effects of technological categories. Given our sample period ranging from 2000-2004, we 18 included dummy variables for year (with 2000 as base) to control for any systematic, yearspecific effects that may influence patents applied for in a particular year. Statistical Approach Because our measure of demand pull innovation ranges from 1 to 7, we employed the double-censored Tobit procedure with a lower limit of 1 and an upper limit of 7. Tobit regression is preferred to ordinary least squares (OLS) regression because OLS can lead to inconsistent parameter estimates when the dependent variable is left and/or right censored (Greene, 1993). Moreover, given that the 8,828 patents in our sample belong to 74 firms, we controlled for firmlevel effects by clustering firms in the regression analysis. This approach is similar in its assumptions and interpretation to a random-effects estimation in a linear model, but allowed us to account for interdependent errors within firms and heterogeneous errors across firms (Glomb & Liao, 2003; Barkema & Shvyrkov, 2007). Because patents can be considered as nonindependent observations with in a firm, the ‘cluster’ function in STATA helped us account for this within-firm dependence and offered greater efficiency for test the heterogeneous errors across firms than would the traditional fixed-effects specification. RESULTS Table 1 reports descriptive statistics and a correlation matrix for the variables used in testing our hypotheses. Stata linear regression collinearity diagnostics produced VIF values that all were less than 4.58 – well below the rule-of-thumb cutoff of 10 (Neter, Wasserman & Kutner, 1985) – indicating that multicollinearity is not a concern in our data. For ease of interpretation, the variables reported in Table 1 are not mean-centered. All the independent variables were centered in all equations in Table 2, however, regardless of whether they were used for interaction terms (Aiken & West, 1991). 19 [Insert Table 1 about here] [Insert Table 2 about here] Table 2 presents the results estimating the likelihood of demand pull innovation. Model I is the baseline model incorporating all control variables. Model II augments Model I by adding the main effects for Technology modularity and Strategic attention focus. Model III adds the Strategic attention focus x Technology modularity interaction term. Chi-square tests show that Models II and III provide significant improvements compared to Model 1, indicating that the independent variables add significant predictive power beyond the control variables. Hypotheses 1 and 2 proposed that strategic attention focus and technology modularity each would be positively associated with demand pull innovation. The results in Model III support both H1 and H2. For the interactive effect, Hypotheses 3 proposed that states that the positive relationship of technology modularity on demand-pull innovation would be enhanced with increases in strategic attention focus on marketing. In Model III, the coefficient of the Strategic attention focus x Technology modularity interaction term supports H3. Among the control variables, Firm patent size has a negative and significant coefficient (p<0.05) and Explorative alliances has a positive and significant coefficient (p<0.05, except for Model 1). These results suggest that firms with a large patent portfolio tend to create technology pushed innovation, while allying with explorative partners will enhance the likelihood to create demand pull innovation. Finally, the year fixed effects and technology class fixed effects are jointly significant, indicating that macroeconomic conditions and technology heterogeneity have an impact on the tendency to create demand pull innovation. We investigated the robustness of our findings in several ways. First, we aggregated the patent-level data to the firm level and calculated an overall demand-pull innovation score for all 20 patents filed by each of our sample firms in each year. This produced a panel-data sample that allowed us to examine the firm-level degree of demand-pull innovation each year for the 74 computer hardware companies, totaling 269 firm-year observations. For this unbalanced paneldata sample, we performed the Hausman specification test to determine the choice of a fixed- or random-effects model (Hausman, 1978). Results suggested that a random effects specification was appropriate, and we therefore used random-effects regression for all our models. To test the overall degree of demand-pull innovation at the firm level, we retained the firm-level predictors used in the patent-level analyses while we aggregated the patent-level explanatory variables to the firm level. We calculated the average self-citation ratio for each firm’s total patent applications in a given year to measure Self-citation ratio (firm). Similarly, we used the ratio of total science linkages over total number of patents to calculate Science linkage (firm). We again applied the method of Fleming and Sorenson (2001) and Sorenson, et al (2006), but at the firm level, to measure Technology modularity (firm). That is, this measure was based on the ease of recombination for all subclasses encompassed in the total patent applications of a firm in a given year. The other explanatory variables, with the exception of Technology class dummies, were already at the firm level, so we kept them in the panel-data analysis without modification. Because the panel data were at the firm level, we were no longer able to control for technology-class effects in the regression. Hence these were the only controls dropped from the panel-data regression. The descriptive statistics and a correlation matrix for the panel sample are reported in Table 3. The means of the variables are slightly different from the numbers in Table 1 due to the unbalanced panel structure. We used Stata linear regression collinearity diagnostics to check the variance inflation factors (VIFs) for all independent variables and interaction terms. All VIFs 21 were less than 5.27, suggesting that multicollinearity is not a concern (Neter, Wasserman, and Kutner, 1985). [Insert Table 3 about here] [Insert Table 4 about here] Table 4 presents the estimation results for the factors affecting a firm’s overall degree of demand-pull innovations. Wald Chi-square ratio tests show that Models 2 and 3 provide significant improvements compared to Model 1, indicating that our independent variables add predictive power to the control variables. The variable Technology modularity (firm) is positively related to a firm’s overall market-pull innovations in Model 3, consistent with our findings at the patent level. Strategic attention focus on Marketing versus R&D is positively related to a firm’s overall market-pull innovations in Model 3, again consistent with our patent-level findings. We also found a positive interaction effect between a firm’s Strategic attention focus on Marketing versus R&D and Technology modularity (firm) on a firm’s overall market-pull innovations in Model 3. The control variables Firm patent size and Explorative alliances are no longer significant at the firm level in Table 4, while the coefficient of Self citation ratio (firm) is marginally negative. For our hypothesis tests, however, the overall pattern of firm-level results closely matches the results pattern we found at the patent level in Table 2. We next performed two additional robustness tests (details of these tests are available from the authors). First, we replicated the patent-level analyses by adopting a dichotomous dependent variable, Demand pull dummy, to measure demand-pull innovation. This variable took on the value 1 when the score of demand pull was greater than 4.0, 0 otherwise. Using logistic regression, we observed a similar pattern of results as that reported in Table 2. In addition, we followed Sorenson, et al, (2006) by using a longer window to calculate the Technology 22 modularity variable, in order to test the stability of this variable over differing time windows. Using a window of 25 years (i.e., 1975-1999), the new measure was highly correlated with the one based on a 10-year window and led to qualitatively similar results. DISCUSSION Technological advances often have been viewed as the most important source for firms’ innovations, which in turn can create and sustain competitive advantage. Yet comparatively little is known about demand-pull side of innovation. Our study contributes to the technology innovation and strategy literatures by investigating factors affecting the degree to which a firm’s innovations are likely to be technology push or demand pull. Results indicate that increases in technology modularity and strategic attention focus on marketing each increase the likelihood that a firm’s innovations will be demand pull. Moreover, the effect of technology modularity on the likelihood of demand-pull innovation is further enhanced as a firm’s strategic attention emphasis on marketing increases. We discuss the implications of these findings next. Implications for innovation Although prior research has discussed the increasingly important role of demand pull innovation in the current dynamic market place (e.g., Di Stefano, et al., 2011; von Hippel, 2005), little is known about which technological conditions or organizational factors can best foster demand-pull innovations. Our study is one of the first investigations this topic. Results indicate that technology modularity facilitates the development of demand-pull innovations. While scholars have noted the role of modularity in addressing heterogeneous market needs (Argyres et al., 2011; Schilling, 2000), much empirical research on technology modularity has focused on the imitablity or transferability of modular innovation (Sorenson, et al., 2006; Fleming & Sorenson, 2001). Our study is one of the first to utilize patent data to investigate the effects of 23 modularity in affecting innovators’ ability to search and integrate market demands into innovations. We provided additional empirical support for the prior theoretical premises regarding modularity, but we also have opened new doors for further exploring the effects of modularity in a broader research context associated with firm strategy. This broader research context adds strategic attention focus as an important construct for investigating firms’ innovation activities. According to Ocasio’s (1997) attention-based view, innovation activities are a type of firm behavior that will be affected by allocation of the limited attention resources in the firm. We found support for Ocasio’s (1997) arguments in the innovation context, because firm’s strategic attention focus on marketing relative to R&D positively affected the likelihood of demand pull innovation in our sample. This finding, together with prior research showing that innovation activities can be influenced by organizational culture (Tellis, et al., 2009), CEO characteristics (Wu, et al., 2005), and CEO attention (Yadav, et al., 2007), highlights influence of context in determining the nature of firms’ innovative activities. Furthermore, we have added an important boundary condition concerning the influence of technology modularity on innovation. Our results show that when strategic attention focus on marketing relative to R&D increases, the positive effect of technology modularity on demandpull innovation is enhanced. This finding confirms that managerial activities that align strategic attention focus with technology characteristics have important effects on innovation outcomes. Implications for the demand-side perspective in strategy Our study also provides support for the nascent demand-side perspective on strategic management, which examines how the heterogeneity of market demand is related to firms’ heterogeneity and opportunities for competitive advantage (see Priem et al., 2012, for a review). One way to gauge demand-side effects is, as we have done, to determine the extent to which 24 important strategic activities such as innovation are spurred by internal technological resources or market segment demands. We did this by responding to calls in the innovation literature for empirical examination of demand-pull and technology-push innovations. Our emphasis on the demand side in this study in no way denies or diminishes the usefulness of technology-push innovation, however. Instead, we demonstrated that innovation can result technology push, demand pull, or a combination of the two; that is, from the joint contribution of both technological competences and market-related competences (Verona, 1999). The computer hardware industry has evolved from dominance by mainframe computers maintaining centralized data, to mini-computers with more distributed data processing, to personal computers giving consumers local data control and manipulation solutions, and now toward “cloud” computing service providers. This evolutionary process has been guided by technology breakthroughs that push the development of innovative products and by market demand that pulls industry competitors toward novel solutions. Neglecting either factor will prevent researchers from reaching a comprehensive understanding of technology innovation. Potential managerial implications Beyond the direct managerial implications that can be drawn from our results, that strategic attention focus and technology modularity affect the likelihood of demand-pull versus technology-push innovations, our results also have managerial implications that can be drawn from our classification of innovation drivers. Classification is the foundation of science (McKelvey, 1982) and is a necessity for effective managerial prescription. Prior research and business textbooks have classified innovations as either: product or process (Abernathy & Utterback, 1978), incremental or radical (Abernathy & Utterback, 1978; Abernathy & Clark, 1985), competence-destroying or competence-enhancing (Tushman & Anderson, 1986; 25 Anderson & Tushman, 1990), modular or architectural (Henderson & Clark, 1990; Langlois & Robertson, 1992), sustaining or disruptive (Christensen & Bower, 1996) and, more recently, radical or generational (Gatignon et al. 2002; Turner, Mitchell, & Bettis, 2010). These classifications have improved our understanding of connections between innovation types, firm competences and innovation performance. Yet, they have tended to emphasize the technological attributes of an innovation (e.g., how radical it is compared to existing technology) rather than the drivers of innovations as either fundamental technological change or the emergence of new consumer needs in a heterogeneous market. Our study contributes to technology classification by highlighting the different sources of innovations labeled demand pull and technology push. These distinctions are important because they give us insight into why innovative firms often have challenges in commercializing their innovations (Danneels, 2003). For example, we can extend Abernathy and Clark’s (1985) notion of “transilience” by examining how firms may integrate demand-side factors and technological details in innovation. They noted that: “Novelty and connection with scientific advance may have little to do with an innovation's competitive significance…reinforces the notion that the competitive significance of an innovation depends on what it does to the value and applicability of established competence – that is, on its transilience (between market/customer linkage and technology impact)” (Abernathy & Clark, 1985: 7). By jointly considering the marketing and technology impacts of innovations, they depicted radical innovation as the product of a firm’s joint marketing and technological competences, and niche innovation as producing new products made from the same technology but that used different market-related competences. Similarly, Danneels (2003) proposed a classification of innovation according to the ability of the firm to use its market-related competences (which he labeled customer competences) and its 26 technological competences. Extending the ideas above, we can derive a two-by-two matrix of technology innovations by jointly considering the two dimensions of: technology push versus demand pull, and incremental versus radical innovation (see Figure 1). This matrix shows the interactions between the direction of knowledge sourcing and the design attributes of an innovation, and thereby provides a richer context and guidance through which managers can evaluate the potential success or failure of an innovation based on their specific context, firm competencies and strategic attention focus. Surprisingly, for example, dominant incumbents often are able to respond effectively to disruptive technologies by serving segments of heterogeneous demand while eschewing imitation of the new technology (Adner & Snow, 2010). This is shown by the Swiss watchmakers that were previously dominant in mechanical movement systems. They were not replaced by the emergence of quartz movement systems, but instead focused on a new market niche comprised of consumers who have high regard for the beauty of mechanical timepieces. This phenomenon is hard to explain through the traditional framework focusing on radical vs. incremental innovation. Adner and Snow (2010), however, attribute this “anomaly” to the existence of heterogeneous market demand. On the other hand, GM’s electric vehicle, EV1, and Apple’s Newton in the 90s should be classified as architectural, radical or even disruptive technologies. Yet these breakthroughs didn’t lead to financial success as promised by received theory. Instead, the failures of GM’s EV1 and Apple’s Newton were largely due to their state-of-the-art attributes that diverged from realistic consumer needs. By expanding the traditional classifications of innovation to include technology-push and demandpull sources, managers can better understand their firms’ positioning for innovation, as shown in Figure 1. [Insert Figure 1 here] 27 Limitations and directions for future studies Our study has several limitations that also provide opportunities for future research. First, our study was conducted in the context of the computer hardware industry. Although our sample was large and representative of computer firms, these firms are more likely to be highly dependent on technology innovation to maintain their competitive advantages than are firms in some other industries. This raises potential questions regarding the generalizability of our results. Arguably, our conceptualization can be applied to explain innovation activities in other innovation-intensive industries. We hope that our work may trigger future studies of demandpull innovation in different industry settings. Second, we focused on technology modularity and strategic attention focus as sources of demand-pull innovations. Demand pull is a complicated phenomenon, however, and there likely are other explanatory variables that could facilitate demand-pull innovations. Future research might integrate other theoretical perspectives and variables to further advance our understanding of this complex topic. Finally, some possible concerns about using patent data to measure demand-pull innovation are warranted. One such concern is related to the comprehensiveness of patents as measures of innovations. Because the decision to patent is itself a strategic choice, not all technological innovations are patented. This concern is minimized in part because the nature of competition in the computer hardware industry encourages active innovation patenting (Stuart & Podolny, 1996). Another concern has to do with “noise” in the patent abstract due to the unique format of patent writing, which can make it difficult to pull data from patent abstracts. This concern is minimized in part because the validity of patent abstracts as a valuable source of information for examining innovation has been established in prior studies (Brusoni et al, 2002), 28 and also because we had active patenting inventors in the computer hardware industry validate our abstract-based demand-pull scale. 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The inside track: On the important (but neglected) role of customers in the resource-based view of strategy and firm growth. Journal of Management Studies, 42: 1519-1548. 34 APPENDIX A An illustration of dimensions of product design and user needs in computers (adopted from Randall, et al., 2007). Product design (parameter-based systems) Processor Display Memory Package XGA/SXGA/UXGA Video card Hard drive User needs (needs-based systems) Display density Viewing distance MS-office performance Affordability Gaming Data storage Integrated devices 35 APPENDIX B Examples of patents along the following 7-point Likert scale of demand-pull: 1. pure theory or method oriented; 2. pure technology (such as chemical materials); 3. technology that can be used in product, indirectly related to customer product, or technology breakthrough for certain specialty; 4. technology that can be used in product that is directly related to customer product; 5. technology that can be directly used by customer through a product or service provided by the company; 6. technology that can be directly used by customer; 7. innovation or technique created by customers or created purely based on customers’ interests. 1. Patent 7130278 by Cisco applied in 2001. Multi-layered cross-sectional diagram of a network A multi-layered cross-sectional diagram and a method of diagramming a network by using the multi-layered cross-sectional diagram are described. The multi-layered cross-sectional diagram exhibits sufficient modularity, scalability, and size flexibility to handle a wide range of networks and to deal with a wide variety of network sizes, including small networks, growing networks, and large networks. In addition, the multi-layered cross-sectional diagram facilitates localized modifications to reflect changes in the network. 3. Patent 6809572 by Cirrus Logic applied in 2002 Integrated circuit with automatic polarity detection and configuration An integrated circuit on a system board is used, for example, in a digital audio device (such as a DVD or A/V receiver). The integrated circuit includes a digital-to-analog converter and the system board may include circuitry to mute the analog output of the device under certain predefined conditions. Because it may not be known in advance by the designer of the integrated circuit whether the circuit is activated by a signal in a high state (polarity) or a low state, the integrated circuit includes a detector which detects and stores the required polarity. When it is necessary for the circuit to be activated, the detector provides a signal of the correct polarity. 5. Patent 7152168 by Cisco applied in 2003 Recharging power storage devices with power over a network A network device is disclosed. The network device includes an incoming power port, an outgoing power port, an internal circuit, and a power storage system connected to the incoming power port, the outgoing power port and the internal circuit. In alternative embodiments, the device may include a power regenerator, a power detector and divider, or a power splitter. 7. Patent 6510048 by Apple applied in 2001. Keyboard arrangement The invention generally pertains to a computing device. More particularly, the invention pertains to an improved keyboard arrangement for use in the computing device. One aspect of the invention pertains to a movable keyboard that can be opened or removed to gain easy access to internal components of the computing device. Another aspect of the invention pertains to a magnetic keyboard securing system suitable for holding the movable keyboard relative to the computing device. The invention is particularly useful in computing devices such as portable computers. 36 TABLE 1. Descriptive statistics and correlation matrix 1. Demand-pull innovation 2. Strategic attention focus on Marketing v.s. R&D focus 3. Technology modularity 4. Self citation ratio 5. Science linkage 6. Firm patent size 7. Firm age 8. Return on sales (ROS) 9. Explorative alliances Mean 3.344 S.D. 0.012 0.182 1.658 0.093 4.761 857.998 14.026 0.08 7.196 0.003 0.008 0.002 0.149 7.871 0.076 0.006 0.056 1 2 0.19 0.04 0.00 -0.04 -0.14 0.02 0.00 0.00 0.06 0.05 -0.08 -0.26 0.00 0.00 -0.10 3 0.00 -0.04 -0.10 0.06 0.00 0.02 4 0.01 -0.01 0.11 0.06 0.14 5 0.00 -0.11 -0.10 -0.06 6 7 8 0.19 0.21 0.33 0.18 0.29 0.16 6 7 8 0.19 0.13 0.50 0.20 0.39 0.18 Notes: N=8828. Significant at the 0.05 level (two-tailed test) when Pearson correlations ≥0.02 or ≤-0.02. TABLE 3. Descriptive statistics and correlation matrix (firm level) 1. Demand-pull innovation (firm) 2. Strategic attention focus on Marketing versus R&D 3. Technology modularity (firm) 4. Self citation ratio (firm) 5. Science linkage (firm) 6. Firm patent size 7. Firm age 8. Return on sales (ROS) 9. Explorative alliances Mean 3.520 S.D. 0.055 0.172 0.018 1.763 0.034 0.070 0.006 6.503 0.949 131.677 19.084 10.751 0.560 -0.251 0.069 3.844 0.273 1 2 0.31 -0.06 -0.21 0.11 -0.07 0.03 -0.01 0.00 0.19 0.06 -0.10 0.03 0.06 0.10 0.02 3 0.17 -0.12 -0.02 0.07 0.08 0.05 Notes: N=269. Significant at the 0.05 level (two-tailed test) when Pearson correlations ≥0.12 or ≤-0.12. 37 4 -0.12 0.13 0.22 0.18 0.16 5 -0.06 -0.12 -0.07 -0.10 TABLE 2. Tobit regression results for the determinants of the likelihood of demand-pull innovationa Variable Constant Self-citation ratio Science linkage b Firm patent size b Firm age Return on sales (ROS) Explorative alliances Model (I) 3.33*** (0.30) -0.16 (0.17) -0.33 (0.24) -0.03** (0.01) 0.01 (0.01) 0.01 (0.04) 0.02† (0.01) Yes Yes Yes Yes Yes Yes Model (IV) 3.15*** (0.24) -0.23† (0.13) -0.24 (0.25) -0.02* (0.01) 0.01 (0.01) 0.02 (0.05) 0.02* (0.01) 0.65** (0.21) 0.08** (0.03) 0.16** (0.06) Yes Yes Yes 14.77*** 13.14*** 12.67*** -13604.33 -13468.72 -13463.53 271.22*** 281.60*** Strategic attention focus on Marketing versus R&D Technology modularity Model (II) 3.17*** (0.25) -0.23† (0.13) -0.24 (0.25) -0.02* (0.01) 0.01 (0.01) 0.02 (0.05) 0.02* (0.01) 0.65** (0.21) 0.08** (0.03) Strategic attention focus x Technology modularity Fixed industry segment effect Fixed technology class effect Fixed year effect F Log Pseudo likelihood -2[L(Reduced)-L(Full)]~ χ2 a N=8828. Standard errors adjusted for 74 firm clusters. Coefficients are multiplied by 100 for reporting convenience. † p<0.10, * p<0.05, ** p<0.01, *** p<0.001. b 38 TABLE 4. Regression results for the determinants of firm-level likelihood of demand-pull innovationa Variable Constant Self citation ratio_firm Science linkage_firm b Firm patent size b Firm age Return on sales (ROS) Explorative alliances Model (I) 3.45*** (0.48) -1.24† (0.66) 0.34 (0.33) -0.01 (0.03) 0.00 (0.01) 0.02 (0.05) 0.01 (0.02) Yes Yes Yes Yes Model (III) 3.40*** (0.45) -1.09† (0.66) 0.51 (0.33) -0.01 (0.03) 0.01 (0.01) 0.01 (0.05) 0.01 (0.02) 1.35** (0.36) 0.20† (0.10) 0.84† (0.46) Yes Yes 0.63 17.59 0.59 34.25** 0.58 38.33** Strategic attention focus on Marketing versus R&D Technology modularity (firm) Model (II) 3.24*** (0.45) -1.01 (0.66) 0.51 (0.33) -0.01 (0.03) 0.01 (0.01) 0.01 (0.05) 0.01 (0.02) 1.17** (0.35) 0.20* (0.10) Strategic attention focus x Technology modularity (firm) Fixed industry segment effect Fixed year effect Rho Wald χ2 a N=269. b Coefficients are multiplied by 100 for reporting convenience. p<0.10, * p<0.05, ** p<0.01, *** p<0.001. † 39 Figure 1. Illustration of a transilience view of innovation Demand pull Risk of inventor dilemma (i.e., if short-term focused, then it can lead to inventor dilemma in Christensen’s sense) Challenging but potential for revolutionary technology (e.g., iPhone, Wii) Incremental innovation Risk of sandy foundation (i.e., technology improvement potentially to be trumped by disruptive technologies) Radical innovation Risk of brilliant failure (e.g., Apple’s Newton, EV1) Technology push 40