Dewey HD2C . MA 1 ALFRED P. WORKING PAPER SLOAN SCHOOL OF MANAGEMENT A THEORY OF lOTER- INDUSTRY WAGE DIFFERENTIALS by Julio J. Roten±)er^ Garth Saloner WP# 1822-86 September 1986 MASSACHUSETTS INSTITUTE OF TECHNOLOGY 50 MEMORIAL DRIVE CAMBRIDGE, MASSACHUSETTS 02139 A THEORY OF INTER- INDUSTRY WAGE DIFFEREOTIALS by Julio J. Roten±)erg Garth Saloner WP# 1822-86 September 1986 Sloan School of Management and Department o£ Economics, respectively. We wish to thank William Dickens, Lawrence Katz and LaiNrrence Summers for helpful discussions and the NSF for research support. M. I.T. ABSTRACT of this paper is to present a modeJ which broadly fits features of Inter-industry wage differentials. of salient some the The purpose Several recent empirical papers have found wage differences accross They also show high industries to be large and persistent. countries. High wages appear to accross occupations and concordance ratios and are industries that have high capital/labor be paid in explains these facts on the basis of Our model highly profitable. individual workers. We firm-specific human capital accumulation by workers and the firm focus on the bargaining between experienced experienced worker over the division of the surplus output an workers We show that produces over that produced by inexperienced trained workers, this surplus, and therefore equilibrium wages of depends on the the capital/labor ratio when the technology has putty-clay features. We also show that when there is multilateral bargaining between all firms and experienced workers, wages also . depend on the profitability of the firm. oo">t 61987 \ I Introduction The purpose fits of this paper some of the salient features differentials. is to present a model which broadly of inter-industry These features are discussed in a wage number of recent papers including those of Krueger and Summers (1986a. b) and Dickens and Katz (1986a, b). of These papers find that inter-industry wage differences are large and persistent. They are also highly correlated across countries with substantial concordance across Western industrial countries and Eastern Block countries. and Katz (1986a) also show that the concordance fairly narrowly defined occupational groups. is Dickens high across One very striking feature reported both in Krueger and Summers (1986) and Dickens and Katz (1986b) is that industries in which, broadly speaking there are more variable profits, and variable costs particular, is i.e. where the difference between revenues greater, tend to have higher wages. In industries with high profits tend to have high wages even controlling for a host of other variables while the same is true, although to a lesser extent, for industries with a high capital/labor ratio. Our model explains these differences on the basis of on-the-job accumulation of specific human capital by individuals . After an employee has accumulated specific knowledge about the important characteristics of his job, like the specific mechanical motions required of production workers, the idiosyncracies of particular filing systems for administrative assistants or the tastes of Important clients for sales personel he than are new trainees (see Becker 1964) automatically mean that more valuable is . This does not a trained individual will receive Suppose compensation than his untrained counterpart. that all workers have the same marginal workers would be willing to the firm more in particular disutility of time. Then long-term contracts that to sign binding involve wages equal to this marginal disutility of time whether they Our model assumes are trained or not. infeasible. There is that such contracts are thus ex-post bargaining between the firm and the worker over the division of the excess output produced by the trained worker-"^. Without more knowledge about the institutional framework for this bargaining it is impossible to predict (or surplus) will be divided. take-it-or-leave first at the which it is it how this excess output Suppose the firm can make credible offers to workers; in other words, it moves beginning of each bargaining period, quotes a wage wUling to employ the worker and is at committed to ignore any counteroffers. The worker can only accept or This gives the firm all the "bargaining power" so it reject the offer. receives all lln the voluminous literature on specific human capital accumulation this bargaining, which Is often not discussed expUcItely, plays an important role nonetheless. In particular, whether in the presence of specific human capital there will be too many quits, too many layoffs or both depends critically on the division of the surplus between workers and firms (see Stiglitz (1974), Salop (1979), Mortensen (1978), Jovanovic (1979), HaU and Lazear (1984), Parsons Stiglitz (1974) and Salop (1979) let the firm unllateraUy (1984). pick wages, Mortensen (1978) studies arrangements which lead to efficient separations whUe Jovanovic (1979) assumes the worker pays for aU his training and receives the value of his ex-post marginal -5- the surplus^. If instead the workers can make credible take-it-or- leave-lt offers to firms they receive we present require only The models that workers receive at least some positive This fraction of the surplus. the surplus. all Is intuitively reasonable for two reasons even granting the ability of firms to acquire reputations of being unbending in their negotiations with workers. First, in the model we present below, firms are ex -ante indifferent between having and having one a reputation for hard-nosed bargaining the present value of their paynments to workers Second, either event. in a richer model is for softness, the same in which workers are in heterogeneous, a flexible attitute in bargaining can elicit information about workers true alternative opportunities and thus avoid inefficient separations. Once one accepts that workers receive some their abUity to outperform trainees difference is we still of the surplus from must explain why this related to industry variables such as profits and the The capital/labor ratio. latter turns out to be a consequence of assuming both that trainees are less productive than incumbent workers and that the technology has some putty-clay features so that the capital labor ratio assumption is is higher value product. fixed ex-post. The to restrict the firm to replace worker with a single output lost is less productive trainee. the surplus to be divided. if it is produced with more role of this latter any given incumbent The difference in This output naturally has capital. To make the role Parsons (1984) surveys some of this literature 2When the firm is uncertain about the alternative wages available Individual workers (as in Stiglitz (1974) and Salop (1979)) it will 1o Output of capital clear consider the following example. by combining people and is buy tractors number Ex- of different sizes. post only one worker works with a given tractor. the same produced Ex-ante the capital/labor ratio tractors. variable since the firm can is If make trainees of mistakes independently of the size of the tractor, the cost of their mistakes will be bigger the larger are the tractors. on the Thus the surplus that incumbents can extract depends size of the tractors The role of profits in a model of this type is less clear because, for any profit maximizing firm, the marginal revenue generated by the last unit sold equals might be seen to imply that the fraction of marginal cost which firm. its most a worker can receive is be shared by workers nonetheless. a is a independent of the profits of the We present two reasons why some workers have This marginal cost. The of the rents of the firm can first is that ex-post, some very substantial effect on firm output (or profits) This would be the case, for instance, for individual computer software developpers working on a large project any one the of them, fall in output slows is down the whole this large, approximated by the units . project substantially. the lost revenues lost times The departure may of When not be well marginal revenue. For instance, in an oligopolistic industry, one would also have to take into account that marginal revenue rises as output contracts. The faster marginal revenue rises the more surplus the worker produces. Insofar industries with steeper marginal revenue curves also have offer some of this surplus as wages to prevent quitting. -7- higher profits this induces a correlation between profits and wages. It must be noted that there an important shortcoming of is viewing each worker as bargaining Individually with the firm after he has acquired specific human capital. This that the is sum of the marginal contributions of trained workers can easily exceed the Then, total value of output. bilateral firm-worker bargaining can A more yield negative profits for the firm. appealing formulation would take into account the mutual interdependence would recognize that more, less is if of workers available for the rest of the workers. Unfortunately, solutions to this n- player noncooperative bargaining problem. Suppose for instance that simultaneously make take-lt-or-leave the sum all workers offers to the firm subject it to the constraint that the firm closes unless If It other workers have bargained and obtained WG do not have good profits. . it makes nonnegative workers of the marginal contributions of exceeds the value of the output this game has a multiplicity of This occurs because equilibria. if 1 believe that many other workers are demanding their marginal contributions to demand less and keep the firm my Many such marginal contribution. Conversely, alive. others to be modest in their demands, will 1 I will if I be content expect ask up to the value of beliefs about others, together with each individual workers resulting offer, constitute equilibria. Given the absence this problem, The solution of a satisfactory noncooperative solution to we consider we consider also a cooperative bargaining solution. is has a variety of advantages. due to Shapley (1953). First, it is This solution unique and explicitely -8- takes into account the mutual interdependence of workers. players are treated symmetrically by this solution, it Since can be thought of as the expected value of what they would obtain variety of noncooperative settings. Finally it is all in a a natural generalization of the Nash bargaining solution for two-person games, for which a noncooperative rationalization does exist. solution, we show that workers, because they cannot Using this be always all regarded as "marginal" workers, receive some of the inframartginal by the profits generated There is firm. an additional advantage of our model using the Shapley This advantage value over that of bilateral bargaining. is that our current model of bilateral bargaining considers only one homogeneous class of capital. workers which obtains more when This a is that all . One workers share employees Involved asssociated with is coupled with more drawback because the perplexing feature inter-industry wage differences different workers it in much of that they apply to a variety of is attractive feature of the Shapley value in the rents that they help generate. is So marketing (who perhaps are not directly capital) still increasing in the capital/labor ratio collect if some surplus that they are needed to is sell goods produced by surplus-generating production workers. Both the bilateral bargaining model as well as the one based on the Shapley value must be regarded as models in which individual workers bargain individualistically with models based on unions in . They thus stand which workers engage in in contrast collective bargaining (for examples see Aoki (1980, 1982), McDonald and Solow As WG discuss further (1981)). in our concluding section, this is an advantage because the pattern of Inter-industry wage differences cannot be explained by unionization alone. The models we consider predict that trained workers will obtain higher wages than untrained workers and that this difference depends on profits and the capital/labor Yet, industries with high ratio. wages wUl naturally attract workers. Thus, if the labor market functions well, the present value of payments must be equalized across industries. This naturally requires that in industries in which incumbents extract high rents, trainees must receive very low (or even negative) payment. at least It is easy to show that in this case, under some circumstances the input and output decisions the firm are efficient. of This results from the fact that the present value of the payments to the different factors equals their opportunity cost. Even will also in this case firms with higher wages for trained workers have higher average wages because, as the future discounted, the reduction in the payment of trainees is the undiscounted increase in the wages of incumbents. is lower than Yet, in computing average wages the wages of trained workers are not Nonetheless, this version discounted relative to those of trainees. of the model has the prediction that differences in average can be explained entirely by differences time. There is at least in the slope of wages wages over some evidence, discussed below, that appears Inconsistent with this implication. If, for some reason the wages of trainees cannot be lower than -10- some value, be wages of It the minimum wage or some "fair" fraction of the incumbent workers one obtains the type of unemployment that has been discussed (1979), Lindbeck by Shapiro and in similar models by Stiglitz (1974), Salop and Snower (1984) and Stiglitz in "efficiency wage" models (1984) and Bulow and Summers These (198G). barriers to low initial wages prevent the equalization of the present discounted value of worker compensation across jobs making some jobs more attractive and generating queus for these jobs. show that these barriers raise not only the wages also those of incumbents since these can more expensive outside workers. We of trainees but now only be replaced with This mean that these barriers only exacerbate the differences in average wages we obtain in our model with market clearing wages. The and profits on average wages effect of capital-labor ratios naturally has the consequence that estimates of profitability or of price-cost margins will be biased across industries. Heavily monopolized industries with high prices wUl tend to have high wages as well so that the usual measures of price-cost margins wUl understate the difference between price and social marginal cost. The paper proceeds as the labor market clears. follows. In section We II start with models in we present a simple which each worker bargains unUaterallly with the firm. III we analyze mutually Interdependent bargains. which model in In section In section IV we consider barriers that prevent the wages of trainees from being low. Section V presents some conclusions and argues that the model also capable of explaining the positive effect of establishment is and 11- flrm size on wages that is discussed in Brown and Medoff (1986). Bilateral Bargaining II We consider capital. Its a firm which produces output with labor production function has constant returns while decisions are taken amount and in two stages, of capital per worl<er is initially capital as well as the chosen. In the second stage employment can be varied but the maxiimjm number of employees that can usefully be employed is given by the amount of capital times divided by the predetermined amount of capital per employee means that capital can be thought of as tractors or workstations whose size used by at is k/n the amount level of employment such = This computer ex ante variable but which can only be most one worker ex post. Letting k denote the level of capital, q . worker and of capital per e the ex post a production function can be written as: ef(k/n). Note that this production function e < n is a returns to scale production function when e (1) standard constant is equal to n . In our model, we also distinguish between skUled, experienced "insider" labor and inexperienced "outside" labor. (1984) when As in Lindbeck and Snower "outside" workers are first hired they are trainees for one period and during this period their productivity fraction a of that of the existing "inside" workers''. is It only a is useful! -12- number to define the [(n-r) + where n or] of "effective" employees z employment and total is which r is the is given by number of trainees employed.^ Analogously to (1) we consider the ex ante production function given by: q = (n - r)f(k/n) + af(k/n) < r < n zf(k/n) = (2) e.Once again, the firm musi choose ex so that z corresponds to ante both the level of capital and that of the capital/labor ratio. Since both k and k/n are point. Our interpretation capital stock to be workers. now and n are determined it (if at this expects the of (2) is that the firm used mostly This means that fixed, k not exclusively) by trained expects output to essentially equal nf(k/n) unless an incumbent worker is replaced by a trainee.^ 3This is superficially similar to the assumption of Shaked and Sutton (1984), that new workers can join the firm only at predetermined intervals of time. In both cases a certain amount of output is lost if the incumbent worker and the firm cannot reach agreement. The difference is that if the wage is subject to periodic renegotiation in Shaked and Sutton's (1984) model, the wage falls to the reservation wage every time the firm is actually capable of hiring outsiders. 41n this formulation it is implicitely assumed that firms never let the total number of employees fall below n. This is not an Important restriction since our model has perfect foresight so that the firm knows how many employees it wUl hire when it chooses k and k/n. It would thus never purchase capital which would be unused ex post. SThere Is a somewhat more general formulation for this ex ante problem that yields essentially identical conclusions. In this alternative formulation the potential use of trainees is Suppose the firm contemplated more directly when capital is chosen is allowed ex ante to pick k, n and r the anticipated number of trainees that wUl work with the capital stock. Let z be [n-(lThen supposing a)r], the anticipated number of effective workers. . -13- Ex post it Is only possible to change r taking k and n as Instead of using (2) directly as our ex post production given. function we sometimes use a slightly more general formulation which assumes that ex post output q = given by: is g(z) where g (3) is a nondecreasing function. considered above the function g Workers have access reservation wage of forever. w'' is zf(k/n). to a perfect capital per period. Thus they are For the particular case First, market and have a we assume that they live willing to join the firm as long as the present value of their compensation equals at least w''V(]-p) where is a market determined discount factor. worker would be willing to accept to Obviously, the least a work in any given period is We thus focus on the most the firm would be willing to pay, the compensation of workers they are able to make take-it-or- leave-it offers. This is if p done with the undestanding on for most that, reasonable bargaining games, the worker wUl receive only i.e. w'\ a fraction that the number of trainees wiU equal r, output is zf (k/z) Ex Then output post, however the number of trainees r might exceed r. equals [z-(l-a) (r-r) ]f (k/z) With r set equal to zero, this Its advantage lies in formulation is Identical to that in the text. that It allows the firm ex ante to hire relatively less capital for The idea of the two trainees (who use capital less productively). production functions is the same. Ex ante workers are substitutable for capital but ex post capital per worker is fixed so that substituting trained workers by trainees reduces output by morte the higher is the capital/labor ratio. The reason for choosing the formulation with r equal to zero is that, if capital is long lived it will mostly be used by trained workers and the firm will lose if it taylors its capital to the abilities of trainees. . . 14- between what the firm y of the diffGrencG With this proviso, make take-it-or-leave pay and wiliing to w''\ both potential trainees and insiders offers to the firm at the beginning of each These offers specify period. to it let is a wage at which each worker is willing Each of these offers can be either accepted or rejected. work. accepted the worker receives the required wage and becomes If it is (or remains) an insider at the end of the period. the individual worker rejected, is If it is not employed and maintains (or regains) the status of outsider. Let the wage of trainees be denoted by wj W2, W3, W4 . . Then that of insiders where the subscript denotes the period . and R(q) be the revenues output. , of the firm when it sells of by employment q units of the following proposition summarizes the equilibrium values of these wages: Proposition 1 The unique perfect Nash equilibrium of the game has wages given by: wi wj - - w* w* = = -pp (1 - (4) P)B i > 2 (5) where P = R[g(n)] - R[g(n-(l-(x))j (6) -15- = (l-a){R'g' - (l-a)[R"g'2 . R'g"]/2i (7) and primes denote derivatives evaluated at r equal to zero Proof: Outsiders will always lower the wages they demand during the traineeship until the present discounted payments of lifetime employment profile of w''/(l-p). is So suppose that insiders ^yj demand a wages whose present value at time is x St- Paying this present value to an insider forever instead of turning to an outsider S^ is - that acceptable to the firm only w*/(l is if wages equals - p) < = R[g(n)] - if RIg(n-(l-a))l (8) the difference in the present discounted value of at most the current difference in revenues obtained (since in future periods the revenues are the same) make take-it-or-leave-it offers they demand hold with equality. a wage This equation implies that S^ is . Since insiders that makes (8) constant over time which implies that wages of insiders are constant over time. Thus without loss of generality equation (5) follows. we can write S^ as W2/(1-p) and Equation (4) follows immediately from the requirement that the present discounted value of wages equal w'V(1- •17- that the typical production worker reduces output so replaced by a trainee that marginal revenue much when he is On itself is affected. the other hand, there are clearly some production and some clerical workers who are pivotal significantly members in any organization and who reduce output when they depart. For them, as well as for the of a smoothly functioning string quartet, important and its end up reflected average wage. to a discussion of the efect of R' To do differential. ex-post production function . ratio remains the same. + in is which constant (2) gives the Thus the The present value capital/labor of the cost of these is vk/n)/(l-p) where v is (10) the rental rate of capital. ratio remains the same, output increases and by f(k/n) thereafter. these inputs generate Since the capital/labor by af(k/n) the first period So, the present value of the revenues is: 6Thus we are neglecting for instance the dynamics associated with all the workers are trainees, output is marginal revenue is correspondingly higher than in later the first period in which low and which R' of firms. Let the firm add one additional worker as well as k/n units of capital forever. (w* in Also we concentrate on the case additional inputs on the wage we consider the ex ante decision so For simplicity we focus on steady states over time." may be relevance even for only a minority of workers may in the We now turn the R" term -16- p) . Equation (7) results from a second order Taylor expansion with respect to r.QED Note that more generally, when W2 - equals approximately (1- w'' p)y(l-o){R'g'-(l-a)[R"g'2+R'g"]/2}, the difference between W2 and wj is given by: W2 (l-a)y{R'g' = wi - - (l-a)[R"g'2 R'g"]/2l + Several comments deserve to be made about (5) (6) , and (9) . the premium earned by incumbent workers over the reservation First, wage (9) proportional to the premium they earn over the trainee wage Is the latter is larger because trainees must "pay" for their jobs by earning less than larger Is the Second, the larger are (1-a) and w''. fall in g', i.e. the output from replacing an incumbent worker with a trainee, the larger is the wage premium earned by incumbent workers Now consider the second order term and ignore g" perfect competition R' zero. is Under . equal to the competitive price and R" For a firm with market power R" is negative and gives the rate at which marginal revenue decreases as output increases the firm perceives a linear demand curve for the absolute value of R" is will be larger and that R" the firm. order term It is its slope. in absolute will It is is its product , . If R" gives thus natural to expect that value the more monopolistic the firm therefre be correlated with the profitability of must be pointed out that the relevance unclear. On the one hand it is of this difficult to second imagine -18- [a If * p/(l-p)]f(k/n)R' the firm is (11) maximizing profits, (10) must equal (11) in a steady state so that R' = (w* whicli + vk/n)/{f(k/n)[p means that, if + (l-p)tx]i we can neglect the second order terms, the premium received by incumbent workers in particular (6) W2 - and w* is = (1 - p)(l-a)(w" +vk/n)/[p proportional to (w"'+vk/n) prove that + (l-p)a] in the capital/labor ratio Independent of the form of the function ratio is ; becomes: thus increasing (13) does not (12) a single firm, f. It is (13) and worth noting that by raising the capital/labor would raise wages of incumbent workers although this foUows Immediately from (6) and (7) as k/n goes up. f (and therefore g') goes up when Instead (13) proves that different firms with different production functions will pay higher wages the higher the optimized value of their capital/labor ratio. is We show below that under certain circumstances this optimized value is actually efficient The reason for this result is that one can always define the unit of output as the amount produced periods. by one worker and the amount 19- by the capital/labor of capital given of the unit so defined only on w +vk/n. must equal The marginal revenue ratio. its marginal cost which depends Replacing one incumbent worker by one trainee leads to the loss of (1-a) units so defined hence the surplus proportional to (l-o) (w' +vk/n) From . (13) is one can conclude that unless the second order effects are important , only the capital/labor ratio and not the level of profits affects wages. Efficiency of the capital labor ratio It might be thought at this point that since insiders some of the compensation due to capital they capture would bias downward the This does not follow necessarily from capital labor ratio of firms. a model of this type as can be seen by considering the ex ante decision problem of firms capital labor ratio they At the moment firms pick capital and the . know expenditures per employee of k/n that the present value of its will be w'V(l-p). optimal choice satisfies: w'^f7[v(p which is + (l-p)o)(f - f'k/n)] = the same as would obtain receiving w* per period. The 1 if workers could precommit possibility that the capital/labor ratio is efficient should not be overstressed relies Thus the heavUy on realistically a single however since ex-ante capital/labor choice. some of the capital is it More purchased after some trained to -20- workers are on the premises capital will be . This may have the implication that chosen taking the dependence of wages on capital Intensity Into account and that capital choice wiU be distorted. ' Putty-clay vs. Putty-putty At this point it is worth commenting on the importance of the assumption of putty-clay technology. If the technology were putty- putty, both the ex-ante and the ex-post production functions would be given by: q = zf(k/z) which corresponds In (1) to allowing ej and e2 post subject to the constraint that they be equal to each other. this case, even with a fixed capital stock, ex to be picked In the loss of ovitput from replacing an incumbent worker with a trainee would only be (l-a)(ff'k/n) instead of the (l-a)f which occurs in our putty-clay model. The loss is smaller because capital can be put to uses by combining it more productive with the more productive incumbent workers. Moreover, we now argue that if the same substitution post as ex ante the capital labor ratio plays no role collected by experienced worker. This is in so because, is possible ex the premia by an argument analogous to the one used above, the marginal revenue produced by similar ex-post inefficiency may arise with respect to labor turnover. This turnover may be inefficiently low due to the presence of high wages after the worker is trained. 7A -21- [a+p/(l-p) ] produced by (f-f'k/n) units of output, the extra output one extra worker that is kept forever, must equal their marginal This means that the loss cost which equals w''V(l-p). replacing one incumbent worker by a trainee, (1 -a) output from in (f-f'k/n) leads to a loss in revenue proportional to w'' and independent of k/n. Average wages and finite horizons So far we have concentrated only on wage premia for experienced workers rather than on average wages. the average lived workers, experienced workers. for such wage is essentially equal to the We now show Suppose that, once an employee (1) in T which periods. first joins the firm, for wages we if T assume that workers remain with the firm only the firm only wage that industries with high workers also have high average workers even arbitrarily in Of course with infinitely periods. he remains with For simplicity we revert to the technology order approximations to the loss from switching workers are sufficient. Again, let in revenue workers make credible take-it-or-leave-it offers. Proposition If workers 2 join the firm only for T periods, the unique Nash equilibrium has constant wages for trained workers equal to W2 These as well as the wages of trainees satisfy -22- wi - w''' = -(p W2 - w* = (1 pT)3/(l - - p)B/(l - pT) (14) pT) - (15) Proof Outsiders will now bid down the entering wage wi present discounted value of compensation value of the foregone reservation wage Insiders who expect employed can, value at to work most expect equals the the present w '(1 -p^)/(l -p) for another to bid a until the periods j . remain will path of wages whose present leaves the firm indifferent between keeping them and Sj replacing them with a sequence of new workers. For the firm to be indifferent: Sj - w^'d - pJ)/(l where the LHS the RHS represents (15). - p) of (13) < B(l - pJ)/(l pT) (16) represents the extra disbursements while the gain in revenue. To demonstrate - that this backwards induction. To obtain is true for (14) it is For j equal to all j one proceeds by enough to 1 w'''(l - gives remember that the present discounted value of payments to a worker [wl pT)w2/(l-p)] must equal (16) + (p- pT)/(l-p) and apply this to (15). Note that the premium paid to experienced workers rises as QED T becomes shorter because the strategy of replacing current experienced workers with trainees means that the replacement for the -23- trainees themselves will have to occurr sooner. This makes this strategy more expensive and increases the value of existing workers. To compute average wages we assume leaving the firm is constant over time. number that the of workers Then average wages w are given by: w = w - [wi w* That + (T-1)W2]/T = P[(T-l)(l-p) this expression is For can be seen as follows. - (p-pT)]/[T(l-pT)j. increasing in T equal to p)/2(l + p) and thus increasing in is increasing in multiplying 3 T and 3. all 2, it is T greater than one equal to 3(1- Moreover the numerator the denominator remains positive for for 3 (17) is of (14) positive so the expression T. Comparison with efficiency -wage models The reason why workers obtain more than in this model is outside workers. their reservation wage that they are more valuable to the firm than Instead, in efficiency-wage models homogeneous productivity wages are high behavior by existing workers^. "efficiency" of workers. effort (Solow(1979)), It to elicit a This change in witli workers of change in behavior changes the does this either by directly increasing reduce shirking (Shapiro and Stiglitz. (1984), SEfficiency wage models also include adverse selection models (Weiss -24- or reduce turnover (Stlglltz (1974, first of these elasticity of Salop (1979)). In the models the wage premium depends only on the supply of effort with respect to the wage and the capital/labor ratio has no role. Stiglltz also 1985), The shirking model has the property that all of Shapiro and firms for which efficiency wages are an Issue pay a wage that prevents shirking independent firm characteristics. This conclusion probably depends in of part on the fact that the susbstitutabUity of effort (or lack of shirking) for number of employees is modelled as independent of the capital stock". On the other hand the turnover-based efficiency wage models are closely related to the model of this Section. 1985) there is a training cost T.^^ In Stiglitz (1974, In contrast to the model presented so far, these models assume that quitting by workers nondegenerate decreasing function of the wage they are paid . is a These models also assume that trainees and experienced workers must be paid the same wage and conclude that wages can exceed the marketclearing level. wage it The reason for this is that each firm raises the pays untU the higher payroll costs are balanced by reductions in quits which translate into reductions in training costs. Moreover, if the second order conditions are satisfied an (1980) in which workers differ in their true (unobservable) ability. a model in which this substitutabUity depends on the capital stock is reaUy not very different from a model in which workers are of differing qualities and high quality workers have a comparative advantage in the production of goods with high capital/labor ratios lOSalop (1979) assumes that the training costs are an increasing convex function of the number of trainees which makes it difficult to analyze the cross-industry effects of different training costs. 90n the other hand 25- Increase in T, which increases the value of keeping incumbent workers raises wages. With the putty-clay technology assumed here, T, the training cost equals (l-o)f(k/n) which, as k/n. for Thus we have shown if increasing in their turnover model can be adapted to yield higher more capital Intensive industries. even is wages This result would emerge workers were allowed to pay for their training because, as above, keeping the present value of wages constant, average wages rise when incumbent's wages Thus rise. the putty-clay technology implies high wages intensive industries even long as quits fall when capital firms unilaterally set the wage, as smoothly with increases assumes instead that workers aU quit while they remain otherwise. in if in wages. Our model they are paid less than w' In this case, workers must have some bargaining power for wages to increase with capital intensity. Ill Mutually Interdependent Bargains The model of bilateral bargaining presented above assumes that while each individual worker bargains with the firm (and threatens to quit) he expects all While this may appear suspect. A more the other workers to remain with the firm. empirically reasonable its logic is somewhat symmetric treatment of the threats of each Individual worker would recognize that other individuals are also threatening the firm and that, were they to leave, the individual's 26- To put bargaining position would be altered. suppose that some of the other workers this differently, in the firm in fact quit, then the additional departure of an individual worker to the firm as long as R" is individual can, in principle, is more costly negative. This means that the demand be paid taking into account to this eventuality. Consider for instance an Economics Department. experienced econometrician is Having one clearly essential to guarantee the quality and continuity of the Department's activities. department has three econometricians each one ought capture some of the surplus he would provide if Even to if the be able to the other two were to leave. To model this ability to capture some inframarginal rents we model a firm with n incumbent workers as an (n + 1) person game which the firm (associated with capital) is in one of the players. Since no convincing extensive forms for games of this kind have been worked out we use an axiomatic particular, since the game solution to this game. well described is by its In characteristic function (see Shubik (1982)), the Shapley value (Shapley (1953)) is a natural solution concept. A second problem with section when g' is is also solved the bilateral approach of the previous by the Shapley value. very large, so that the departure very costly. Then the sum bilateral bargaininng of all the This problem arises of payments any one worker to is workers using our approach may exceed the revenues of the firm. In some sense this problem is due to the fact that workers are only •27- bargalning with the firm instead of bargaining with other workers as This well. naturally taken care of is when the n workers and the firm are being viewed as bargaining at once. We by considering only simplify the analysis somewhat a single period and considering the ex-post technology (1) with the function g given by the product of f(k/n) times its output a = is The firm argument. an imperfectly competitive markets and in demand curve q its its perceived given by: bp - where p sells (18) the price for the good. is Total revenues from employing r trainees and (n-r) experienced workers is: R(r) The = [a - f(n-(l-a)r)][f(n-(l-o)r)/b characteristic function, denoted v, (19) is a function from subsets S of players to real numbers which gives the maximum revenue by cooperating. that the subset of players can obtain incumbent workers are symmetric coalitions with j workers with characteristic function is without capital for which The most in is capital, v(0,j). this coalition can obtain is all the our example we consider only for whom the value of the v(k,j) and coalitions of it Since Consider jw'' j workers first the latter. since their special skills can only be exercised together with the capital they arp familiar 28- with. Now consider the coalition of capital with (n-r) experienced This coalition workers. trainees and pay will find to each. w''' It it in its interest to hire r thus obtains the revenue given by The marginal revenue from the expression in (16) minus rw''. replacing an additional incumbent worker with a trainee can be (to first order) approximated -m A = m = 5 = - Cr (l-a)f(a - 2n)/b r is the current a) times the marginal it is number By of capital. Note that m is (1- the argument of the previous equal to (1-a) times the marginal cost of these Thus for r equal to zero, this approximation neglects the second order terms considered in (17) of trainees. revenue associated with one additional trained worker and (k/n) units inputs. (20) 2{f(l-o)}2/b where Section by: The approximation used in Section 11. can also be used to approximate (16) for any value of r. It gives n-1 R(r) = v(k,n-r) = R(n) + I ( m + U) - rw"' i=r where (21) is used to define the value of the characteristic (21) 29- function associated with any coalition of capital together with (nr) incumbent workers. Now we have expressed the characteristic function we can that calculate the Shapley value for each player written, for example, as i . This value can be ^j: n+1 *1 = I (l/c(j)) I [v(S) v(S-{i|)J/(n + l) - (22) j=l where v(S) is the value of the characteristic function associated with the coalition S. Thus each player receives the average of his marginal contributions To compute he contributes. by Shapley to all the coalitions to this value we use the procedure proposed This procedure considers (1953). ordering the players. which For each ordering it all (n + l)! ways of attributes to any given player (l/(n+l)!) of the contribution he makes to the coalition of the players that come before him. We obtain <^y, = w* + ^y^ for m/2 + workers and ^j^ for capital: Un-l)/6 (23) ^k = R(n) - nw''' + nm/2 + n(n-l)^/3 30- When workers come "before" capital they receive w" come "after" they contribute w'+m even when thus always includes half the time and after half the time It The term is C m split is 50/50 with capital. capital earns R(n)-nw''' by using thus guaranteed at least this amount. captures the Increased marginal revenue of Inframarginal units. In particular it higher for steeper demand is curves and zero for horizontal demand curves. Workers as a whole receive only 1/6 of the total revenues that depend on capital receives 1/3. whenever The average zero. is Since each worker comes before capital w''. Even without any incumbent workers, n trainees, 5 when they ; The reason for this uneven capital comes after at least some ^ while splitting workers it is that receives the revenues of the early, most valuable, units. One interesting feature of (23) is that as n rises the compensation of each worker rises proportionally to n^ seem paradoxical since it leads to higher wages. says that a larger level of employment must be kept It in mind however that n represents the optimized value of employment. that the it demand curve to hire into A higher n thus means of the firm has a higher intercept more workers. which leads This larger demand naturally translates more equilibrium surplus some of which goes Since firms with a higher of This may . ^, to the workers. which can be interpreted as degree monopoly power, have both higher profits (compensation capital) and higher wages, our model predicts between profits and wages. to a positive correlation This means that the level of accounting -31- profitabllity may considerably understate the level of actual profits. At this point the reader may wonder what Aren't we simply asserting that the payment to one factor capital. depends on the worth ? If so, special about is why should of the other factors with worth vary across goods this this question is that it which he is capital is combined The answer ? which becomes less productive to if combined with trainees while each individual worker has the same option as any trainee, namely to leave and earn his reservation wage. This does not mean that incumbent workers need to be interact with capital directly in order to receive premia for their experience. enough It is that they enhance the productivity other workers who do interact with capital. To see we turn of to a simple three agent example. The three agents or denoted m denoted s for factors we consider are manager whose reservation wage for secretary whose reservation wage each are available at the same wages. function of the game v(k,m,s) = v(k,m) = pp - v(k) = ap v(m) = Wm is Wj Wjn - is Wj^, Wg. We assume the a worker and a worker Trainees for characteristic given by p - is capital, Wj where p can be thought v(m,J) = w^ v(k,j) = ap + - Wj Wp, v(j) = Wj of as the value of the output In this -32- example the replacement of incumbent output by (l-p). output of m by a trainee does reduce This however can be interpreted as a loss m is is an incumbent or a trainee. because when whether a regardless of s s replaced by a trainee output (2-a-3) can easUy exceed Section II 1 falls to Note that example the sums of the marginal contributions of In this in the m and which makes the solution proposed s, in problematic. The values of the game to k, m and s are given by <^]^ , and ^j^ respectively: *k = v(k) *m = v(m) *s = v(s) + + + p[(l-a)/2 p[(l-a)/2 in last s m team. equally as (l-P)/6] earns more than his reservation wage (which happens players) he receives (l-3)p. and - (l-P)/6] p(l-B)/3 The reason why when he comes - is in is that 1/3 of the orderings of This compensation to s is shared by k the surplus (l-a)p from having an incumbent Note however, that the dollar surplus of s depends on p which, once again, depends in equilibrium on the amount of the factor without alternative uses k. IV Constraints on Trainee Wages So far we have assumed that the labor market clear.s in the sense that trainees upon joining the firm can expect to earn no more 0g -33- than the present value of their reservation wages. requires that trainees earn very pattern that is in high wage industries, a not borne out by any available evidence. ^^ a particularly severe problem our model. little This however This under one natural reinterpretation is of In this reinterpretation trainees are no less productive than incumbents but (1-a) units are lost in the transition, perhaps because all it takes time to recruit trainees. This would imply that wages are the same but that new hires would have sum payment to the firm, The extent to much to make as in efficiency- wage models which trainees pay for high paying jobs some extent an open question. a lump "^^ is to Yet, the empirical evidence on tenure, while not narrowly focused on this question, does not support the notion that trainees earn particularly wage industries. of tenure First, Abraham and Farber little in high (1986) find the effect on wages to be relatively small once one controls for the ultimate length of the job^^. Second, Katz (1.986) reports that An alternative which may be more realistic in some environments for trainees to work hard at a host of more menial activities in addition to perfoming the tasks in which they are replacing a (more 11 is productive) incumbent. The value of these more menial activities would then have to be subtracted from the trainee wage to obtain our measure of wj 12In efficiency-wage models it is often argued (Akerlof and Katz (1986)) that capital market imperfections prevent such lump-sum payments. In the presence of these imperfections efficiency-wage models tend to Imply that firms can gain by paying entering workers low salaries and making them perform tasks for which efficiency Thus insofar new hires do not receive wages are not important. low wages in high wage industries, some doubt is cast on efficiency wage models as well. ISAdmlttedly, for a large fraction of the sample, the ultimate lenth measured to be an increasing function of actual tenure. Their paper is closely related to Altonjl and Shakotko (1985) who show that there if one concentrates only on the effect of the growth of tenure on wages (and ignores the effect of the level of the job is -34- Inter-lndustry wage differences for workers with less than one year of tenure and those with more than ten years are highly correlated. In this SGction we consider industry wages in our model if briefly the behavior of inter- for some reason pay entering workers low wages. As is it impossible to is apparent from the analysis of Salop (1979) and Lindbeck and Snower (1984) such constraints also Induce unemployment. Another obvious consequence is as these that, constraints make labor more expensive they distort the capital/labor ratio. We consider two such constrainst on entering wages. is that entering least wages must equal, perhaps for some minimum level w. sociological reasons, fraction X of the The second is The legal reasons, first at perhaps for that, the entering wage must equal at least a wage paid to incumbent workers. In both cases we conclude that the imposition of this constraint raises wage.s for experienced workers. Moreover, average wages continue to be higher the higher would have been wages for experienced workers in the These increases absence of the constraint. to the question of the wages naturally lead what other constraints prevent wages from growing without bounds. end in Two such constraints are discussed at the of this section. For purposes of this discussion we adopt again the analysis of the beginning of Section 11, though little would be altered considered the multilateral batgaining of Section III. wages) one finds only small effects. we Before computing equilibrium wages under the two constraints we of tenure on if it is -35- useful to prove the following lemma that relates wages of experienced workers to the present value of payments new workers to W. Lemma 1 Suppose new workers earn make take-it-or-leave-it offers Then, a present value of W. to the firm, wages of if they experienced workers, W2, are at most given by: W2 = (l-p)(3 where P, + W) given in (7). is Proof The firm can earns W in either keep the insider or hire an outsider present value. W2/(l-p) - W < It will keep the insider only who if: (24) P. So that an Insider who makes take-it-or-leave-it-offers he demands a wage given at most by (24). Suppose that, starting workers earn W2. period, wj, W is in the QED second period of employment Then, whatever the value given by [wi + pW2/(l-p) ] of the so that, wage at in most: the first 36- W2 < (3 + wi)/(l-p). (25) Three conclusions emerge from The equality. (25), first is that increases in assuming it holds as an wj, due for instance to The second Increases in w, raise W2 and thus raise average wages. is that increases in wages. continue to be reflected 3 in higher average we see that even constraints on wj, do not Finally, eliminate the prediction of the model that there must be a difference between W2 and wj and that the difference between (l-p)w2 and wi must be increasing Now suppose in 3. that the entering wage is given by X times W2. This gives a wage for experienced workers of at most: W2 = which 3/(l-p-X) is finite (26) only X if is less than (1-p); otherwise incumbent workers are always cheaper than trainees and can thus demand up to higher are X an infinite wage. and Again (23) implies higher wages the 3. Since (22) and (23) can give rise to very large wages indeed we now discuss two limits on wages. First, wages of workers can never exceed their ex-post value marginal product R'f(k/n) which course increasing in (k/n) with this analysis is that X So one possibility that . is is is of consistent one and that both trainees and incumbent workers receive some fraction of R'f with the other -37- fraction going to the firm. no slope In the In this case there would, of course, be wages received by workers over time. Second, the firm might hire some workers as "supernumeraries" whose main function is to be already trained (or semitrained) and The presence thus reduce the bargaining power of existing workers. workers has the effect of these and thus lowering of raising o the wage firms must pay to existing workers. 3 and Yet the analysis of the equilibrium with such supernumerary workers is a far from trivial task. For instance, suppose that the firm has two workers for each What should each worker demand the n tasks. or-leave it offers? Suppose there firm will cease to exist. if that each worker will demand, taking the other worker's offer as given effectively competing in Bertrand fashion to equal at w Even the other can demand more than knows that more to the willing to if if w''\ To in pay a premium above He can do will it the last period w'' to they are ; . consider see this, one worker the firm fires him at this point remaining worker w" worker are constrained most twice the reservation wage. . is This should not be . to a single the period before the last period he can make take-it a last period after which the is Then the most viewed as predicting that wages demanding is because he this have The to firm pay is the supernumerary worker in order to maintain the threat against the other worker. Nonetheless we expect that some supernumerary workers will in of a realistic be hired able to contribute to production somewhat. , model of this kind, particularly if these are A richer model might -38- have firms with liigh capital/labor ratios and high rents spending more on labor both through high wages and through excessive employment V Conclusions The basic message of this paper is that the pattern of inter- industry wages appears consistent with a model in which three trainees are not as productive as conditions are met. First, Incumbent workers. Second, technology has some putty-clay features. Third workers have some bargaining power so that the wage somewhere between the wage It-or-leave-it offers could make take- would quote if it and the worker would quote if he could. a firm is WhUe replacing this third assumption with the requirement that quits are a smooth function of the wage also implies that capital/labor ratios are correlated with the wage, our form of bargaining is probably required to obtain corrrelation between wages and profits. This naturally leads to the question of the relationship between our model and models based on collective bargaining. One natural advantage of considering only individualistic bargaining as we do is a union that the public goods problem inherent is avoided-'^'*. On is the formation of the other hand some workers are clearly 14In Aoki (1980, 1982) this problem appears to be circumvented by letting the "representative (incumbent) worker" bargain in a two- person game with management. Yet, unlike what is true when each worker bargains individually, he does not take into account that the demands of other employees alter the opportunities of any given employee. Aoki requires instead that the representative worker that other workers wUl act exactly as he assume, when bargaining, 39- capable of overcoming these problems. In models in which unions maximize some measure of member welfare it of course not is surprising that workers can extract some monopoly rents or even some of the quasi-rents produced by The capital. difficulty with ascribing wage differences to collective action on the part of workers is that it is difficult to imagine collective the absence of institutions such as unions. including bargaining Yet, most U.S. workers, many high wage workers are not unionized. This has led Dickens (1986) to postulate a model The threat of unionization can lead to high wages. workers in in in idea which the is that some sense prefer to avoid the coordination costs of forming a union as long as they do not earn wages much below those they could obtain will if they did organize a union. take actions that prevent union formation either raising wages or making raising employment or both. explaining it more Thus empirical difficulty with this model is This includes difficult to this why high wherever unions . Firms, in response, form a union by model has the potential of could obtain high wages. that, as shown in Dickens and Katz (198G) high wage industries also pay high wages and professionals who, Similar difficulties arise in the US, are very unlikely when attempting The to managers to unionize. to explain the relatively high correlation of inter-industry wage differences accross countries In which unionization countries in which It Is is easy and the Eastern Block essentially impossible (see Krueger and does. This ensures that workers obtain what is in their collective bring about self Interest much as conjectural variations equal to the monopoly outcome In oligopolistic markets. 1 -40- Summers (1976b) who report between log wages of .78 a correlation between Germany and the USRR) It . would seem that our model which requires only bargaining with the individual worker, plus a modicum of self interest on the part of the firm, is better suited to Eastern Block countries. Our paper has focused exclusively on inter-industry wage differences yet ther appears just as is is one other source of wage differences which difficult to reconcile with standard models. This the widely documented effect of employer size on wages which discussed in Brown and Medoff (1986). of the establishment They show and the employer for which positively correlated with wages. They argue a is that both the size worker works are that these effects actually occurr within certain industries are are thus not directly due to inter -industry To explain wage differences. this fact one would naturally need to know establishments and companies within industries differ all in first size. why If firms are competitive and have access to a contant returns to scale technology such as (2), firm and establishment size are Indeterminate and nothing ought to depend on these sizes. suppose that there firms is market power in the industry. Clearly large now have larger surplus but not necessarily larger surplus per employee. Suppose however that the products actually differentiated. of the firms are Then our model based on the Shapley value has the potential for explaining these size effects. that Now if the slopes of the demand We have shown for various goods prodviced with the same technology are the same, larger product lines generate more -41- Brown and Medoff surplus for each worker. (1986) argue that larger firms actually have a smaller elasticity of demand. Yet, their estimates suggest a steeper slope for larger firms which is consistent with more surplus in these firms. A second explanation for differences in company and establishment size is the presence of some entrepreneurial ability which has diminishing returns. This means that there are Inframarginal rents which are bigger in larger firms (establishments) will . In a model based on the Shapiey value workers extract some of these rents so they firms (establishments). It will be paid more in those must be noted that both these explanations are consistent with the collection of facts Brown and Medoff (198G) present to reject other theories of the size effect. In particular, workers in these high paying jobs will quit less and they will lose their high wages if they go to smaller firms or establishments REFERENCES Abraham, Katherine and Henry Farber: "Job Duration, Seniority and Earnings" National Bureau of Economic Research Working Paper #1819 January 198G . 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