ALFRED P. WORKING PAPER SLOAN SCHOOL OF MANAGEMENT A PARTIAL EQUILIBRIUM MODEL OF DERIVED DEMAND FOR PRODUCTION FACTOR INPUTS Nalin Kulatilaka WP 1176-80 October 1980 MASSACHUSETTS INSTITUTE OF TECHNOLOGY 50 MEMORIAL DRIVE CAMBRIDGE, MASSACHUSETTS 02139 A PARTIAL EQUILIBRIUM MODEL OF DERIVED DEMAND FOR PRODUCTION FACTOR INPUTS Nalin Kulatilaka October 1980 WP 1176-80 This paper is part of a larger study attempting to reconcile disparate results in the KLEI-I literature, headed by David 0. Wood at the Energy Laboratory at MIT. I thank Professors Robert Pindyck, Tom Stoker, Ernie Berndt, and David Wood for comments on an earlier draft, and also Professor Joanne Yates for editorial assistance. Abstract This paper presents a model of aggregate production in the conjugate The model provides a technique to infer dual, cost function framework. full equilibrium properties of equilibrium data. In a technology from the observed partial particular, we use a three-factor (KLE) model, assuming capital to be quasi-fixed in the short run, and therefore in disequilibrium, while assuming that labor and energy adjust rapidly to equi librium values. The partial equilibrium model is estimated using two sets of data: time series data on U.S. manufacturing (Berndt-Wood) and pooled data on OECD countries (Pindyck). properties. The results are used to infer full equilibrium These equilibrium levels of capital are compared with the observed disequilibrium data. actual Results indicate divergences between and full equilibrium levels of capital. This casts serious doubt on the validity of the equilibrium specification used by previous authors. Furthermore, substitution elasticities between the factors were computed for the partial-equilibrium (short-run) and full-equilibrium (long-run) situations. These values are then compared and contrasted with the original work of Pindyck, Berndt-Wood, and others which assumes all factors to be in equilibrium. We conclude that under an equilibrium framework, time series data give elasticity estimates that are close to short-run values obtained via the disequilibrium model, while pooled data give values close to long-run values. This analysis does not resolve the E-K substitutability/ However, we are able to eliminate the complementarity controversy. short-run versus long-run nature of the results as a cause of the controversy. An extension of this analysis, where the data construction and specification differences are taken into account, method to resolve this issue. r^L4-\ M-H-M- is suggested as a 1. Introduction In recent years economists have shown a renewed interest in the structure of industrial production, and in particular the substitution possibilities between input factor prices. The sudden price increases of input factors, specifically those of energy, were largely instrumental motivating these studies. But the major analytical tool in that made these studies possible was the introduction of the flexible functional forms by The ability Diewert (1971) and Christenson, Jorgenson, and Lau (1971). of these functional forms to specify and estimate the technology without placing a priori restrictions on substitution possibilities made them attractive for impirical work. The numerous empirical studies that information regarding the relationship followed, while providing valuable among input factors, have also created conflicting evidence. From a policy point of view the most disturbing difference relates to the degree of substitutability between capital and energy. A reconciliation of these estimates requires a careful procedures and the data used by the different studies. look at the Most of these estimates were based on the assumption that observed factor demands were in equilibrium. In this study we use a partial equilibrium factor demand model of the technology and thereby test the validity of the equilibrium assumption. The results are also used to reconcile the question of whether earlier results pertain to the short run or the long run. A full equilibrium static model to their in the assumes that firms adjust all inputs long-run cost-minimizing value within one time period. real world there is However, little reason to believe that factors adjust that rapidly in response to exogenous changes in price or output. fact, for sticky and irreversible factors such as capital, In the observed 4 utilization level will most certainly depart from the equilibrium levels, especially during periods of rapid factor price changes. One way to remedy this is to use dynamic models where the factor adjustment processes are made explicit. These models, however, suffer from the ad For example, Berndt, hoc nature of the hypothesized adjustment process. Fuss and Waverman (1977, 1979) model the intertemporal to minimize the cost of adjustment. disequilibrium is In adjustment so as their framework the only cause of assumed to be the costs of adjustment. They neglect many other sources that could create stickiness in factor adjustments, and therefore such models could lead to incorrect results. The model used in this paper does not explicitly specify the adjustment process. Instead, we arrive at the familiar dichotomy between the short run (where long run (where all some of the factors are in disequilibrium) and the factors are in full equilibrium). A partial equilibrium model shall therefore provide an accurate and convenient way to model the production process. We use this model to perform empirical tests on two different data sets: time series data on U.S. manufacturing from 1947 to 1971 and a set of pooled time series-cross section data for OECD countries. technology is modeled via energy (E) — translog quasi-fixed. a three-factor — capital cost function where capital (K), is The labor (L), and assumed to be The results indicate very small departures between observed and equilibrium levels of capital for the time series data, but larger differences in the pooled data sample. support of the conventional claiiTi The results also provide some that time series data reflect short-run behavior while cross-section data reflect long-run behavior.^ 5 The paper proceeds as follows. the model In Section 2, a verbal description of and its uses is presented as motivation for the more formal development that follows later on in the section. Section 3 presents an outline of a framework for using the partial equilibrium analysis towards the reconciliation of disparate results in the KLEM literature. In Section 4 we present and interpret results from applications to Berndt-Wood time series data and the Pindyck pooled data. Section 2. Finally, in we make some concluding remarks. 5, The Model and Its Uses Our study differs from previous industrial factor demand studies in its partial equilibrium specification of the technology via a restricted cost function. the model and In its Section 2.1, we describe the assumptions underlying mechanics to prepare the reader for the more formal development of the model in consider a a special case, Section 2.2. in Section 2.3, we KLE translog technology where capital assumed to be quasi-fixed, which will 2.1 Finally, is later be used in empirical work. Motivation and Description of the Model Traditionally, economists have modeled the production technology of firms in a static full-equilibrium framework. In the event of changes in factor prices or the level of output, these models assume instantaneous adjustment of all input factors such that total costs are minimized. However, is very in the real world where factor adjustment unlikely that such technology. a is slow and costly, model would be an adequate description of it 6 To remedy this, more recently, some researchers have used dynamic models, where the factor adjustment processes are explicitly specified. adjustment mechanism, of course, The exact nature of the intertemporal depends on the condition that is assumed to cause disequilibrium. such models can be found in Berndt, Fuss and Waverman (BFW) 1979). Two (1977, The first rrethod assumes lags in adjustment to be the cause of disequilibrium and therefore the process is modeled by distribution. In the more a Koyck lag sophisticated second method, they postulate adjustment costs as the cause of slow adjustment. Then the adjustment takes place along a path that minimizes the costs of adjustment. Although conceptually appealing, both versions suffer from the ad hoc choices of the lag structure and adjustment costs. Even more importantly, other considerations stemming from government regulation, the differential treatment of investment and costing decisions within organizations, and the physical inability to change inputs (due to irreversibility or lags) are neglected in such dynamic models by not providing complete treatment of the causes a their analysis. Therefore of disequilibrium can lead to misleading results. An alternative approach is to consider a dichotomous situation between the firm's technology in the short run (the immediate time period) and the long run (some unspecified time after the immediate time period). This partial equilibrium approach is more general than the extremely restrictive full equilibrium approach, but does not provide a detailed description of the intertemporal behavior as given by the dynamic models. However, unlike che dynamic .models described earlier, the adjustment process in partial equilibrium models can accommodate any or all of the causes generating. the short-run disequilibrium. 7 Therefore, we feel such a model would provide a simple but realistic framework for aggregate production analysis. The theory used in these partial equilibrium models is well in the traditional developed microeconomic literature where costs are broken down into fixed and variable parts. (1980) use such a model In a recent study Brown and Christenson to study the substitution factor inputs in U.S. agriculture. possibilities among Their model of the farm sector assumes self-employed labor and farm land to be quasi-fixed. The results indicate that the observed levels of these quasi-fixed factors differ from the full equilibrium values predicted by the model. They also obtain short-run elasticities that are significantly different from the long-run values, thus indicating slow adjustment of these factors. These results, by exhibiting the power of the partial equilibrium technique, provided the initial motivation for this paper. In this paper, we will be more precise about the mechanics bringing about the partial equilibrium model. consists of two stages. In The firm's input choice decision the first stage, firms adjust the variable factors to minimize variable costs. This minimization takes place within the time period in which changes in factor prices or output levels occur. The other factors need not be rigidly fixed but they do not adjust to the long-run cost-minimizing equilibrium levels. them quasi-fixed factors. Hence we call The resulting technology is in a temporary (short-run) equilibrium, which is described by the restricted (short-run) cost function. In the second stage, firms aojust quasi-fixed factors until the total cost is minimized. initial time period. This adjustment takes place after the end of the The resulting cost function characterizes the 8 Hence, we arrive at the long-run (full-equilibrium) technology. dichotomy between the short run and the long run. This two-stage optimization model features. If the observed interesting leads to several levels of the quasi-fixed factors are equal to the constructed full equilibrium levels, then a full equilibrium model would adequately describe the technology. However, other in all situations, the full equilibrium specification will result in an inaccurate description. Hence, by using a partial equilibrium specification, we will do at least as well as the full equilibrium specification. Even though we can differentiate between short-run and long-run properties, this model is essentially in a static framework. The second-stage optimization does not feed into later results. cost function is only a The long-run theoretical construct used to describe the situation where all factors are utilized in the most efficient manner. 2.2 A Formal Development of the Model The theoretical basis of restricted cost- and profit functions were developed by McFadden (1978) and Lau (1976) in their seminal work on the uses of duality theory in production economics. the relevant results that are to be used in Consider a Here I only summarize later applications. n+m factor production technology where in the short run only n factors are variable. The other m factors are quasi-fixed in the short run and these will be called the quasi-fixed inputs. observed technology will be in partial equilibrium. Then the This short-run technology can be characterized by solving the following cost minimization problem: CR = Min. P . X s.t. Y = F(X, Z) where X and P 9 levels and prices of the variable factors, Z is a m are vectors of the vector of quasi-fixed factor levels, the production function. is function can be written as: However, in long run, the Y is the level of output, and F(.) When minimized over X, the restricted cost CR = CR(P, Z, Y). the firms can adjust the quasi-fixed factors and thereby reach the full equilibrium which is characterized by the following total cost minimization problem; Min CT(P, Z, Y) + Q Z, . C = Min CT(P, Q, Z, Y) = where Q is the vector of the quasi-fixed factor prices. The first-order condition of this optimization problem is ICR (1) Eq. (4) + Q = can be solved to obtain the full equilibrium values of the quasi-fixed factors, Z*. in terms of the Then the long-run cost function can be written restricted cost function and the cost of the quasi-fixed factors as: C (2) = CR(P, where Z* will be a Z*, Y) + Q . Z* function of P, Q, and Y. We now have complete characterizations of the technology in both the short run and the long run. These cost functions can be used to evaluate expressions for the substitution elasticities between the input factors. The short-run Allen elasticity of substitution between factors i and j is given by: CR CR ^ ' . . °ij " CR. CRj where the subscripts of the cost function denote its partial derivatives with respect to. the factor prices. Similarly, the long-run Allen 10 elasticity of substitution between factors C , and i can be written as: j C. The most interesting feature of this model is its ability to represent long-run properties via the short-run (restricted) cost function which can be estimated using observable data. C, C^. and C . can be written in terms of CR, In other words, its derivatives, and Z*. These results are given in Brown and Christenson (1980) and we summarize them below. S=TPT-^ '=' where b^. = if i e V =1 if i c F and we define the set F such that set V such that (6) i e -^ V if X^ = C. 3P.3Pj IJ . ^-S *i^jr^ is a L?CR_ ^ 3P.3Pj. F c i p,^, if X. .b..z. 1 is a fixed 1 factor and the variable factor. V ^ '^k 3P.3Z*^ ^ W ^y '^k 3^CR ^ ^iZ^^p, 3^CR aZ* 3Z^*3Z* iPT^ + b At the full equilibrium the terms in the curly brackets in equation (6) will go to zero since equation (1)) for all k e |§¥ + P^ = (from the first-order condition in F. To complete the computation of a method of evaluating these values ^'s L , • vie . , . need to evaluate aZ* ^, A general given in Brown and Christenson, but for the special case considered in this study we were able to derive a simpler method. The re?t of ' ,s paper will focus on this special form of the problem which still capt-res the gist of ^he disequilibrium 11 concepts and also provides set of interesting results when applied to a particular data sets. A Special Case 2.3 To proceed any further with this analysis it is necessary to characterize the restricted cost function by form. (L) In this study deal with a three-factor technology where we and short-run variables whicle capital and energy (E) be quasi-fixed. particular functional a labor is assumed to By modeling the industrial production technology by only these three factors we are making an implicit assumption about the separability of K, L, and E from non-energy materials and other inputs. As a suitable functional form for the restricted cost function, we choose the translog form (see equation (7)) due to its ability to make a good second-order approximation while maintaining flexibility of substitutability between factors. (7) In CR = a + oy In Y + Y + iZ Z ^ + i=L,E j=L,E £ i=L,E S a. In P. 1 1 Y.. In p. In p. 1 J .^^^^ iJ p^. In Y In P. ^' ' + S i=L,E + In K + B. K - Yw^n ^ YY Y)^ 'TVi^nnK)2 KK 2 p_ In P. '^ ' In K + t: In Y In K For purposes of this study, we introduce a number of constraints on the cost function. In addition to the usual neoclassical properties of homogeneity of degree one in factor prices and output, symmetry of the second order cross terms, we also impose the further simplifying assumption of long-run constant returns to scale. Under these assumptions the cost furction can be written as (see Appendix derivation) 1 for 12 In CR = a^ + ay ln(Y/K) + a^ (8) + ^ ln(PL/P^) - y^\_{'^n{PJP^))^ + Pyl InCP^/P^) j n(ln(Y/K))^ ln(Y/K) + In P^ + In K An application of the Shephard's Lemma yields the variable factor share equations: (9) \ (10) Sg = = - Yll T^(Pl/Pe) " f^YL \ - 1 - aj^ ^^^"^'^^ Yll ln(PL/''E^ " ^YL P.X. "^^^^ ^- = P.X. = P.X. Z ieV ^ "•"^Y^'^) "CR- ^ The full equilibrium cost function for this special case simplifies to: (11) C = CR(Pl, P^, Y, K*) + P^ K* and the first order condition of cost minimizing becomes where K* is the equilibrium level of the capital input. aCR Evaluating the partial derivative, -^[^ for the translog function in equation (7) and substitution in equation (12) gives: (13) CR(P, K*, Y). where Aj = 1 Equation (13), - oy + a (Aj - tt ir In Y - In K*) Py,^ + P^ K* = ln(P|_/P^). non-linear equation in K* can be solved to obtain the equilibrium values K*. For this particular functional form (or for many other commonly used cost functions) form solution to (13). used in solving for K*. it is not possible to obtain a closed Therefore, numerical simulation techniques are 13 As seen in Section 2.3, the partial problem is the next step in computing a-- derivatives of ^p- . is to obtain For the single fixed factor case the greatly simplified from the general case mentioned earlier. By implicitly partial differentiating equation (13) with respect to the factor prices and solving for aK* N . (S. _^, aK* —r- we get: V.P^^) for (14) - N'^ where N = A, and V. - ir In TT i = L, E - N K* if i = L if i = E = 1 +1 and^ (15) aK* _ JO^ ^''k ^K N (N^ - it - N) Once the equilibrium capital Remaining terms in level is known the expression of c th-;se , values can be evaluated, are summarized below: 14 =0 if i ^ Observe now the following two properties (partially differentiating (14) with respect to K* and P.): 2 (20) -^ /9i\ ^ a^CR 3K aP. ^,,2 = 1 3^CR ^ ^ |^+ Substituting these r fPoN ^^^^ Sj = 3K _ - n 3P. equation (6) yields: in 9^CR aP.aP. ^ a^CR aP.aK* iKl aP. ^_Ar_^ if n i i, if i i c j c V v V j e F aP.aK* aP^ if i, j = K* e F Similarly from (5) C. (23) =p^S. if i e V = K* if i e F We can summarize the computations as follows: obtain K*. Then compute ^ First, solve (13) to and the partial derivatives of CR from i e quations (14) - (19). Finally, 3. Compute C • , C-j using equations (22) and (23). substitute these in (3) and [7) to get the elaticities. Framework to Reconcile Disparate KLE Results approach One of the most interesting uses of this partial equilibrium stems from its ability to distinguish between the short-run and the long-run characteristics of this technology. This provides us with a 15 framework to address some of the issues which are thought to generate disparities in aggregate factor demand studies. to review the Here, we do not attempt literature on industrial factor demand studies. Instead in this section we develop a framework by focusing on two aspects which are likely to contribute towards the disparities. The first concerns specification of an equilibrium cost function, common to all studies generating the initial E-K substititability/complementarity debate. The second focuses on the short-run versus long-run nature of the results obtained by previous researchers. Specification Test 3.1. A The validity of the equilibrium specification can be tested by comparing the actual level of capital, K, with the full equilibrium level, K*, obtained by solving eq. 13. If departures between the two paths occur, then that would invalidate an equilibrium specification, thus casting doubt on the results stemming from such a model. A formal test of the hypothesis K = K* requires information on the distribution of K*. But since eq. 13 does not have a closed-form solution for K*, and can only be solved via numerical methods, we are unable to compute o standard errors of the estimates for K*. The results of thi specification test are, however, still conditional on the assumption that some of the factors reach long-run equilibrium instantaneously. For example, in the KLE framework, if we allow only capital to be quasi-fixed while labor and energy are at their full equilibrium levels, then the results are conditional on this assumption. capital is Therefore, finding that the full-equilibrium level of not significant V, different from the actual observed level may 16 validity of the full-equilibrium not be sufficient to conclude on the specification. the actual However, if we do find significant disparities between conditional on the and equilibrium values under this model, levels, violation of assumption of observed equilibrium labor and energy conclusion. this assumption will only enhance the In other words, we can but not to accept it. use this test to reject the hypothesis 3.2 9 Short-Run/Lonq-Run Controversy econometricians has been to The conventional wisdom among applied cross-section data as capturing interpret elasticity estimates based on time series data as long-run effects, while those estimates based on capturing short-run effects. Pindyck (1977) and Griffin and Gregory paper by Houthakker (1965). (1975) trace the origins of this claim to a Stapleton (1980) makes references to a paper by Kuh (1959) where he equilibrium is slow, estimates points out that, if adjustment to long-run estimates are likely to reflect based on cross-section demand-function reflect only partial long-run elasticities while time series estimates adjustments. series data is used Evidence from pooled cross section-time differences in by both Kuh and Houthakker in showing the considerable cross section as compared with coefficient values obtained from a single those based on time averages. Pindyck (1977), using pooled cross tests this hypothesis section-time series data from ten OECD countries, informally, and finds the results to be inconclusive. earlier addresses this issue The adjustment cost literature mentioned by explicitly modeling the adjustment path. But, as pointed out earlier, conditions about the causes and these studies assume rather restrictive nature of the disequilibrium. 17 this paper, we only consider the polar cases: In is within one time interval, and a time after the end of the period. a short run which long run which is at some undefined To address the reconciliation issue via these estimates requires careful consideration of the data and the validity of the original estimates which assumed all factors to be in equilibrium. If the previous analysis does not indicate any significant differences between the actual and equilibrium levels of the short-run fixed factors, thereby justifying the specifications used by previous studies, then we can make direct comparison between the corresponding elasticity estimates obtained via these two specifications. For example, we should check the following relationships: TS S L ^ij " °ij < °ij xs a . . 1J = a s . . 1J > a . . IJ where a..'s are the elasticities of substitution between factors j. The superscripts TS, XS, S, and L i and denote times series, cross-sectional, short-run (restricted), and long-run (full-equilibrium) cases, respectively. Since these estimates are random variables, the above relationships should be checked via significance tests. as mentioned earlier, the procedure used in However, this paper does not provide a facility to readily compute standard errors of the elasticities. However, if the discrepancies from the equilibrium are very large and significant, then the elasticity estimates of previous models (hereafter I will refer to them as "equilibrium" models or "original" models) difficult to interpret. In such a case, it is necessary to evaluate the elasticities on different data sets (time series and pooled data) on the 18 same or at least similar technologies, if one is to to resolve the long-run versus short-run debate. 4. Empirical Application conveniently lends itself to The methodology developed thus far established data on aggregate empirical applications using previously industrial production. In this section we use the restricted cost technology for two data sets, one time function to estimate the short-run section-time series, to estimate. series and the other pooled cross The then used to compute the full procedure described in Section 2.3 is elasticities of equilibrium levels of the quasi-fixed factors and long run. substitution in both the short run and the 4.1 Data Because this paper is part of a larger reconciliation study, the most that created the initial logical data to be used here are those controversy. features Convenience as well as some characterizing (B-W) (explained later) led to the choice of Bernt-Wood (1975) time to 1971 and Pindyck (1977) pooled series data on U.S. industries for 1947 for 1963-1973. cross section-time series data on 10 OECD countries detail sets of data are explained in considerable original papers. Carson (1978). Both in their respective found in Further details on the Pindyck data can be several other data A critical analysis of these two and data construction methods, can sets, paying much needed attention to the by Hirsch (1980). be found in an unpublished memo 19 Several caveats with special relevance to this particular technique need mentioning. The first concerns the data on level of output. In the orginal B-W study the cost function specification did not include cross terms in factor prices and output. Therefore, the output term did not enter into the estimation of the factor share equations. Pindyck incuded such cross terms in his cost function and used the "net value of output" for Y in the share equations. This amounts to using real values as instrumental variables for the level of output. (deflated) In this study we estimate the entire short-run cost function and thus need a measure of the level of output. We obtain this by constructing output price as a divisia index using arithmetic value weights and price of the input factors. Diewert (1977) has shown that the divisia index forms and exact index in the case of a translog technology. Therefore we have an exact index of the input prices and the divisia 'output' The of the KLE input. index for B-W data are plotted in Figures 1 The and 2 respectively. divisia indexes for each of the 10 countries in the Pindyck data are reported in Table 1. The level of output is obtained by dividing the value of output by this divisia index. Second, aggregation. it should be kept in mind that the data 1s at a high level of The conditions for the existence of aggregate production functions are extremely stringent and it is very conditions would be met by the data used here.-^^ unlikely that these Although most studies have this problem, researchers find that the 'reasonable' empirical results obtained by such aggregate analysis provide some justification for using such data. 7 Thirdly, the price of capital short run and in the long run. that this price is a rental P. is assumed to be the same In this in the analysis it is crucial to note price of capital and not an asset price. 20 Figure 'i)d e.-40 1: B-W Prices for K, L and E. 21 :,, -..i t^ CD ^3 -2 •<; •*C ^-^ G-^ D 4^-. r- O'J- >.> .^2 G-- to CO n in ^: ?o f-s U-; IX t-i O f-" Gn O ^ -^-^ L;:i O !~n r-i C-i • m : -U Cs; Cl iii :! l; r-j r^ rs f-s lt •«;Cs -O Tn t;- LO ti COOO ^ <- -V 0^ C^ D; ^ V^ CO C4 T-0^ ^- 0- "J r-s c-.i C^^ i2 ^'^ .: C-j --; O^ -a CN ^ O c- c: , O C"4 Si <j 0^- ^"^ ^ -:2 o ^-^ 02 Ci O Ci O XI u oc en (U <; r CD Vi 11 Ci sO N-; rx fV <T u •f— •O Vi CN to '4 r^ O < a o : : <i fi -^ CO fO <?" t; r) rn r^ CO •^ >:-: f^. f^ n r-i r'^ li s c^- ?i ^i •o T-f '4 -. i( II '••, f>s o ^ rs c^ o o LI c-> r-i n ^ c^ 0^ T-! o ui <r ir: it: CO ^j Ch r-v r-4 rs -4 ^- <T Ci s- o u n 3 3 ri >c ^ o a 0-. 04 f^CD fo t^ <? L") •^r CO ~o CO r^ r-. ro ri r-4 r; >o c?c-i r^ t? l:; cp 0^ r^ ro tn ?/} :; r; k/^ ^-f -O ^"5 ' X x» c • i-i o w •>* o o i. n t-i li i! ;i n II >- o M ^ G-' o- rv r-^ rH in «-: a:•.*«•; ro r: ro -r-; 0^ -rn CO -r-i -c -O <5- rj ^ f'i r-4 r-4 •< •r"r- > n ^v n |N n o rp o ^ ^^ ^ LO ro CO ro ro o <r >c CO ^ Ci "4 C; r- r-4 XI g: r^- Cr- r-": i;"; •h"! *"• T-! C-- I! li n •>C D-* ^~^ -^r t-i o^ «r iiO -o r-- c; cs <D 'O ^C S3 -O ~0 r- Ts D* D^ G-^ 0"^ 0"^ 0"^ 0^ 0-* <? ^r c i Ci CO r-^ -o &• ^. c-< <> D- ir; ri =-h r- ^d •« C4 10 in r>. !> p:; ^^ -; 04 '4 r-4 ro in no^ » ^» > » -» II 11 m | ii , ii ; :: I o r4 ho ;;-= ^^ •<? uo -c rs cd cso so s-0 so >0 Sj ^C Ts Ts T-^ f^. Cs 0C- CC Gs CCS CC?- C?- :: i; I! 22 4.2 Estimation of the restricted cost function Due to the full equiibrium nature of the specification used in the original papers by B-W and Pindyck, it was sufficient to estimate the factor share equations to obtain the relevant substituion properties. However, as seen in Section 2.3, in this partial equilibrium set-up we need to estimate the entire restricted cost function to obtain the Although there does not long-run values of the quasi fixed factors. exist simulataneity between the cost function and the share equations, the error terms of these equations are correlated. To account for the contemporaneous correlation of the errors, we use Zellner's seemingly unrelated regression (SURR) to obtain estimates of the short-run parameters. Details of the error structure and the estimation technique are given in Appendix 2. are reported in Table In the case The estimated coefficients for both data sets 2. the translog form described of B-W data, 16 provide a good fit of the short-run technology. in eqs. 15 and However, for the Pindyck data, the fit was not that good (see column 2, Table 2) coud be attributed to a number of reasons. This First, as Pindyck notes in his paper, the assumption of a homogenous production function across the 10 countries in the sample, is not justified. To remedy this, he allows the intercept terms in the share equations to vary across countries. Fuerthermore, he finds that a better specification is obtained if U.S. and Canada are pooled separately from Japan and Europe. allowing such difficulties. a On this study specification would create significant computational A more sohisticated computational procedure that is currently being developed, would enable us to carry out more realistic specifications in the next stage of the study. results \/ery soon.) (I hope to have these 23 Table 2 SURR Estimation Results: (1) Restricted cost function: (2) Labor share equation: eq. eq. (10) (9) 24 Second, even within the specification used here, we notice that the coefficient ir, has a low t-statistic, indicating its insignificant contribution towards explaining the dependent variable (see column Table 2). 2, An alternative specification, where the cross terms between K and Y are omitted (i.e. with column 3, Table 2. tt These results are in = 0), was estimated. To test the null likelihood ratio test as follows; hypothesis of it = 0, we construct a The likelihood ratio test statistic, can be written as: -2 In where = N In ^) ( are the determinants of the estimated error and covariance matrices for the restricted and unrestricted models respectively, observations. is the likelihood ratio and N the number of Under the null hypothesis, this statistic will be distributed as chi-squared with degrees of freedom equal to the number of restrictions. 2 X. The computed test statistic of 0.0936 is value at 75 percent of 0.1015. rejected. In what follows we use lower than the Thus the null hypothesis cannot be this constrained specification with all 10 countries pooled together. 4.3 Equilibrium levels of capital, K* Once the parameters of the short-run cost function is estimated, we use eq. 13 to solve for K*, fixed capital. the full equilibrium values of the quasi Values for K and K* are compared in Figure 3 (for B-W data) and Figures 4a-4j (for Pindyck data). Before commenting on these results, we define "over capitalization" 25 R5 o I CO ta Q. <j «»- o v> > E =3 •I— i- JQ 3 C7 =3 4-> <U CO <u J- a 26 Figure 4. Actual and Equilibrium levels of Capital: P ndyck data 4a. CANADA 155. 135. 115 1968 1963 4 b. 1973 FRANCE 190. i7e. ISO. • 130. lie. 1963 1968 1973 27 Figure 4. cont. Actual and Equilibrium levels of capital: Pindyck data. 4 c. 25©. ITALY 28 Figure^, cont. Actual and equilibrium levels of capital: Pi'ndyck data. 4e. NETHERLANDS. sa. 65. 59< 3S. 1963 1968 4f. 1973 NORWAY 25.0 ee.e 15. le.e 1963 1908 1973 29 Figure 4. cont. Actual and Equilibrium levels of capital: Pindyck data. 4g. SWEDEN S9, 82. 1963 1968 4h. 2S9. - ise. lee. - U.K. 1973 30 Figure 4. cont. Actual and equilibrium levels of capital: Pindyck data. 4i. 1969. 176e. 1560. 1360. iiee. - U.S.A. 31 and "under capitalization" as situations where K > K* and K < K* If K = K* then the observed respectively. technology will be in full equilibrium and the short-run and long-run properties will be identical. In K the case of B-W data, over most of the range, differences between and K* (see Figure 3) are small. During 1958-1961 we observe over-capitalization, while in 1953-1958 and in 1968 we observe under-capitalization. the range, an Upon casual observation we feel that, over most of equilibrium specification would provide an adequate representation. To formally test the hypothesis of K = K* it is necessary to obtain the standard errors of these estimated levels of K*. Unfortunately, since closed form solutions do not exist for eq. 13, we are unable to compute the standard errors of K* without resorting to non linear numerical techniques such as monte-carlo simulations. In the cae of Pindyck data, the differences between K and K* are considerably larger than in B-W case, for most countries in the sample. We observe over-cpaitalization for France (Figure 4b), Japan (fig 4d) and W. Germany Figure 4j); for Sweden (Figure 4g, U.K. U.S.A. (Figure 4h) and the (Figure 4i) the situation is reversed, to give under-capitalization; Canada (Figure 4a) and Italy (Figure 4c) exhibit over-capitalization in the first half of the sample period and under-capitaliztaon in the second half; the two variables are closest together and cross over several times The Netherlands (Figure 4e). in cases of Norway (Figure 4f) and These results indicate significant departures between full equilibrium and the observed data. Thus, an equilibrium specification, as the one used in the original study may lead to incorrect results. Cut before concluding on this issue, necessary to keep in mind tli- it is inadequacy of the partial equilibrium 32 specification which assumed countries, as a homogenous technology across all 10 a model of the true underlying technology. The errors thus introduced could have caused the observed discrepencies between K and K*. However, since the partial equilibrium model possibility of full equilibrium as a includes the special case, this method will always be superior to the full equilibrium specification. 4.4 Substitution elasticities Short run and the long run : The elasticities of substitution computed via the algorithm in Section 2.3 are given in Tables 3 and 4 f(or the short run and the long run respectively) for B-W data. A summary, giving the mean over the sample period for each of the 10 countries in the Pindyck data are reported in table in Appendix 3. 6. The inter temporal details f the Pindyck case are As with the K* values earlier, here too we are unable to compute the standard errors of the elasticity estimates. For the B-W data, the elasticity estimates of L, E own- and cross-effects show very little difference between the short run and the long run (see Tables 3 and 4). This result is to be expected due to the closeness of K and K* values discussed short run LE show substitutability. the previous section. in In the substitutable with both enregy and capital. In the long run labor is found to be But, as with the original B-W study, we still find EK to be complements. The long-run elasticities, than the short-run values, o, s o. . o. p and orp respectively. , is large only in the case of LL. a, ^ s s . and Orr are consistently greater , This difference Since the elasticities are dependent not only on the parameters of the static cost function but also on the data it is possible to computp estimates for each time period (see 33 Tables 3 For There are some noticeable trends in these results. and 4). example, all of the short-run elasticities have decreasing trend over long-run values in table 4, show a downward The time (see Table 3). a trend for LL, LE and EE, but have an upward trend for LK, EK and KK. To test the hypothesis that "time series data captures short-run effects," we consider the following relationship described in Section 3. s a • — a • TS • • L < a IJ IJ • IJ where a-- refers to the elasticities resutling from an equilibrium specification of a LKE model using the B-W time series data. results together with Tables 3 a summary of the short-run and long-run values from are given in Table 5. and 4, standard errors in columns variation over time. These 2 that the It should be noted and 3, Table 5, only take into account the The estimation error component of the variance in the elasticities are not computed due to the problems mentioned earlier. Therefore, we are unable to perform any formal tests on the above hypothesis. Hence, we form a heuristic test by considering the interval within two or three standard deviations around each variable. left hand side of the above relation, we compare columns To test the 1 and 2 of Table 5. overlap within 2 The hypothesis can be accepted (i.e. standard errors) only in the case of the ar-c- intervals ^or o. . and o.r the short-run values are much smaller than the time series estimates in column 1. However, the right hand inequality (compare cols. 1 and 3, Table 5) is found to be satisfied in all except a^^ (where the time series values are larger than the long-run values). In the case of 0^. , the inequality will be true only if we form intervals using 3 standard errors. But here again, if estimation error in the partial equilibrium 34 Table 3: Short-run Allen Elasticities: SZLL 1947 —J sua -0. 071907 --.0-085 28 1_ - 1949 -0.03558 j.s.5a -^tO-077.7J_._ 1951 1952 1953 -U. -0.072615 1954 ___ 1955 1956 .„. _- 0.417835 —0.-4530.23 0. 453 74 —0.. 4 33093. 0.419868 _0^ 4.23 3.77._ -0. 071191 .-0. 07 03 53,. .^.0.413 309._ -0.070215 0.412899 _-C..071795 ^0.4175.13 3. 407 83 -0.066519 0,0 6,6.3 63_ -0. 60018 .-0.06 024 4 ..- 1959 1S6 1961 -0.058737 —1962 •ZLE .C.A7335.6,. 1957 .._.1.S5 8 B-W data. _-.0.056.823.„| 0.415763 __0.._4 0A22.1_ 0.380411 —0.331 137_ 0.375965 _0.. 35 9.153_ 1963 -0. 052741 0.353912 „_.1.96.4 --C. 052965 1965 _.0..354.77J_ -0. 050243 = C. 048324 -0. 047155 ...J.966 __ . 1967 __1S6a 1969 -0, 044525 -0. 44 162 _ ...IS 7.0 .r0.042S83 197 -0.051165 1 0.344073 _ 0.336 2 35 0.331339 .0.319 953 0. 310345 _0...:O30 32.. C. 347757 SZEE J- -2.42796 -^2.-4 653 -2.40571 -•^.-42269. -2.42772 ^2.JJ2J -2.42809 -.-2. .4 2 80 9 -2.42807 ._-2. 42799 -2.42744 I' _ji2.it255J. _1 -2.41117 ..-2.4 1193 -2.40648 --2.39822 -2.3749 ^.2*JJ.64J__ -2.35635 33958 -2.32821 _.r2. ^.-2.29917 -2.29477 I i J ^j:.2,.2737J__j -2.36361 j " I I I I cr>T-=r,-; I viJc~>»— r^f^orj"— rnvorg tria-iriuorvjvo lu^ or~^oeNirik;>i-'iLDnrMt— cr> , >x)a-io»— cr>f^jcrvonr-or~; ^ o fM to vu r- r^ fN a> »^ «— CI r> C3 cTi ro r^ oD ^r- o4 CO 'r) rr vD lo <",• i-T r-4 cr> =>" (N =r ri (NJ fN| fvj f\) cN ro ") fs| «- CN f>j CM rsi o o t-0 ir ro f^ rn ' ' > n f'l ro I • rn, Il ro f'l • I rn ri rn I I I r-1 ro (') I I I ^ <^ ro ~i I I I cr> -o rsj <N ^ r>j Lf> lti «- ,— rsi rJ m c> rCM rn en r^ rv4 tN ri uo ^ rn ro ro rn I I I II (•! I o rn ro i; I il, ••; II. » II II' CO tn CM ococ^jr--'— C7» II! CO CO vo ui uo II; n 11- » eg II i cnaDroooa-ovxaj^tMr-r^mro,- 'lo-i'— vD'^OLicnr^r-fo'— II :< ^ '^'~v£;'~mcn;}-vj— vOcr>cri»— T— p-53-r-u'iir;cr><x3"^cri r-ir»or--»£>crCDir>^Torvit~*rM^cDcr33Lninronvo^^r— )> I I r-- cr\ r-^ I I ai « I r-4 I m I r^ ro j^ ^crvor-<-irncccM.^'-oco<i)CD CN (M ^^ I I tT> I ir> r-- I I o^ I oo I I i : »— 1,-1 I • I i ! I jn crvLnir.|a-po'^cncji^'rNiOr-vor~«— !«— in vo rII|VO in =r III CO en en II n II rsj cpi «— vjjcoo cror>'~r^'mrMvi,r\jr-oiocnvon-)r~r^fxi «— «— *"»— «~. »— i^r^r-i'— »— T-oo»-:r^j'~»— r~. p-):cnn^cr>rN» cr; 1^'— v£>vO\D CD' . r~ ;! •— In in CO rM;ir> cr r« <^ cr> »— cri r- o r-, viJ hJ M lljOoCJoOoOOOCDOOIoOOOO OO o c? o o o O II! II : 1 CO I It! I Hi ! Hi ; m to CJ : I II •r- II o •i; •r»-> II i 10 'i II I ^o 0) w S) M II II III III Hi i. I c o <u JQ ftl CM r~ kO CM=j-, rornr~rM;c7>crcr>cocrv «— cot—. rnc^jrocNcoLnroc3r-in-nccincr>vO on CO o CTv^ cr>oo^^moi— oocnao ii,cricofococr>c&ocT>cr>cococn, c^>c^l^^c0 II CI cr> 3-criinoj::3-crN'or^incNioo\a^rsiroco:^ II'• fsi fij I ; +> •r- i II 35 II ..I I ilico »; O O o c^ .1 i II II' c^ II ;: ir IT) IT, c^J lt* vij I II. : 36 Table 5: Summary of Substituion Elasticities: B-W data Partial Equi librium Model 2 37 model taken into account, the results would be even stronger. is In summary, we conclude that an equilibrium time series model captures some but not all of the long-run substitution effects. For the Pindyck data, the long-run own elasticities are consistently larger than the short-run values (compare row row 9, Table 6). 1 with row 7 and row 3 with But the cross elasticity between L and E is indicating larger values for the short-run than in the long-run. between a. and a.r are still small. ^ The differences As with the B-W case, LE and LK show substitutability, but unlike the B-W data, we find EK also to be substitutes in the long run. Thus, the EK substitutability/ complementarity controversy remains unresolved. Nevertheless, we have found an interesting result by being able to conclude that the causality of the controversy does not stem from the time series and the cross-section nature of the data. We now go on to use these results to test the following hypothesis; elasticity estimates derived from an equilibrium model using pooled cross-section - time series data, captures the long-run effects in the As described underlying technology. in Section 3, this test can be conducted by checking the following relationship: cs s CT . . IJ < a L - a 1J . • 1J CS where a., is obtained by estimating an equilibrium model on the Pindyck cross section - time series data. cs Results for a., obtained by Pindyck * are given in Table 7. u As with the B-W case, the test will be conducted in a heuristic manner. In the short-run owfi E and L elasticities are much lower than those obtained via the cross-section specification used by Pindyck. Thus, 38 39 o OO u-> CO i-l oo O oo tM CO On >-i r^ i-t CO O o t-t I < to :3 o oo r>J CTl r-l OO CO 1-1 \0 cs od o oo rH CO CM <r« to oo -3- tM CM x-* t CO CM vo 00 *0 iH r». O oo oo to lO CO o oo r^ CO o co tr> oo oo _J CO CO rH <7\ CM -<f '-A O I ^-' O OO r-i CO rH O OO CM CO O^ oo \o CO CM vo CO 00 <-( o o o- o oo — \0 CO o oo cv OO u-> CO CO o 1-^ r-i oo oo I I -a o o o u-l r-t •H O oo m CO O oo VC CO -» « o c D O O c u 1^ CM CO p. oo O oo 0^ V» CM I 7^ H .J <: < .-I CM \0 O 40 we have evidence supporting the relationship. inequality in the above The LE values for most countries lie within 2 standard cs deviations of a.r, these results. left hand but since In the L s o. r a. it r, is difficult to interpret long run, own elasticities are much closer to the cross-section results than with the short-run cases. countries, fall within 2 or 3 Values for most standard deviations of each other. long-run cross elasticities are even better agreement. one standard deviation for many of the countries. The They fall within Therefore, on this heuristic level, the evidence indicates convincing support for accepting the hypothesis. 5. Concluding Remarks In this paper we modeled the industrial production process in a partial equilibrium framework where some of the factor inputs are assumed to be quasi-fixed to vary in the in the short-run. By allowing the quasi fixed factors long-run, we can make inferecnes about the full equilibrium (long-run) behavior. In particular, we KLE production function where capital is consider a 3-f actor assumed to be quasi-fixed in the observed data. A restricted cost function is used to estimate the technology, in two empirical applications. short-run One of the most interesting results stem from the differences between actual and equili^brium levels of capital. be small. For the B-W time series data, these differences are found to But for the pooled Pindyck data, we notice large departures between actual and equilibrium capital levels. Although the tests used here are not formal, we employ heuristic methods that indicate these differences to be significant enough to invalidate the equilibrium 41 Furthermore, since the specification used by previous researchers. partial equilibrium model contains the full equilibrium model as a special case, it is always safe to use such a partial equilibrium specification in modeling a technology. The fact that actual capital departed significantly from equiibrium levels also has interesting policy implications. For example, the "under capitalization" observed in certain countries could be remedied by policies which would increase incentives for higher capital investment. Increasing investment tax credits or permitting firms to depreciate capital costs more rapidly (e.g., to expense all capital costs with one year lag, as suggested in the U.K.) could provide such incentives. On the other hand, when "over capitalization" is present the policies should aim at achieving the opposite effect. However, specific policy recommendations require the use of more sophisticated models. These models show disaggregate to identify particular sectors where the effects are strongest. Substitution elasticities between the input factors provided another host of intersting results. First we observe that the long-run elasticities are almost always larger than the short-run values (i.e., no over-shooting). This can be explained by a slow adjustment process. Second, the time series models such as B-W, seem to underestimate the long-run elasticities but overestimate slightly the short-run values. The pooled data gave full equilibrium elasticities that were close to the corresponding values obtained by Pindyck. results in a It is hard to interpret these straightforward way, because of the large departures from the equilibrium. However, we can say this: the long-run estimates obtained via ful equilibrium models, are closer to short-run values when 42 using time series data but give estimates closer to long-run values when using pooled data. This can be thought of as the appropriate modification to the claim made by Pindyck (1977) and Griffin-Gregory (1976). This analysis was not able to resolve the E-K complementarity/ substitutabi lity debate. E Even under the partial equilibrium assumptions, and K were found to be substitutes when using Pindyck data but complements when using B-W data. However, we can now eliminate the short-run/long-run nature of the result as the cause of the disparity. Thus, data construction and coverage issues may be at the heart of the controversy. An extension of this study where the data would be adjusted to acccommodate accounting and other differences would convenient vehicle to address the above issue. serve as a 43 Footnotes- Isimilar disparities were observed in the literature on Berndt (1976), in an attempt Capital-Labor production function studies. alternative estimates to reconcile between of elasticity of substitution, found that the results were very sensitive to data construction techniques. ^Griffin-Gregory (1976) and Pindyck (1977) make this claim. •^See Berndt, Morrison and Watkins (1980) for a comparative assessment of dynamic energy models. ^Although we refer to it as a disequilibrium, this can also be This is made clear in the thought of as a temporary equilibrium. description of the model which follows. ^Here we do not attempt to review the literature on industrial factor demand studies. ^Computing such values necessitates the use of Monte Carlo However, we simulations, which were too costly to be carried out here. can make subjective statements by comparing the time paths of K and K*. ^Although I do not have a rigorous proof, the following heuristic Suppose, contrary reasoning might be helpful in providing some insight. Then, to assumption, observed labor is not at the equilibrium level. solving the long-run total cost minimization problem we would have extra In other degrees of freedom over which the optimization can be done. in labor levels changes for adjust words, capital quantities will have to as well as their own changes. o Note that here we assume separabiity of KLE from M and therefore the value of output will refer to the sum of the KLE inputs in this value added framework. ^Hirsch (1980) has taken a closer look at the validity of some of the assumptions behind the existence of aggregate production functions In the context of the KLEM literature. He finds the aggregation problems to be extremely serious but reasonable empirical results are considered as providing some justification. •^^It is straightforward to compute the usual own and cross price elasticities of demand from the Allen elasticities: Ti . . 11 = o . . 11 S . 1 and n . . ij = a . . 1J i • J this paper we only deal with the Allen elasticities which should be interpreted as indicating substitutabi lity if positive and complementarity if negative. In 44 References Berndt, E.R. (1976), "Reconciling Alternative Estimates of the Elasticity of Substitution," Review of Economics and Statistics ( REStat ) , Feb. 1976, 58, pp. 59-68. Fuss, M.A., and Waverman, L. (1977), "Dynamic Models of the _, Industrial Demand for Energy," Electric Power Research Institute Report EA-500, Palo Alto, Nov. 1977. (1979), "Dynamic Model of Costs of Adjustment and Interrelated Factor Demands, with an Empirical Application to Energy Demand in U.S. Manufacturing," Discussion paper No. 79-30, University of British Columbia. Catherine Morrison and G.C. Watkins, (1980), "Dynamic Models , of Energy Demand: An Assessment and Comparison," University of British Columbia, Resources Paper No, 49. and Wood, D.O. Demand for Energy," REStat , (1975), "Technology, Prices, Aug. 1975, 56, pp. 259-268. and the Derived (1979), "Engineering and Economic Interpretations of , Energy-Capital Complementarity," AER vol. 69, no. 3, June 1979, pp. 342-354. . Brown, R.S. and Christensen, L.R. (1980), "Estimating Elasticities of Substitution in a Model of Partial Static Equilibrium: An Application ot U.S. Agriculture, 1947-1974," forthcoming in Berndt and Field, eds.. Measuring and Modeling Natural Resources Substitution , MIT Press (1981). Carson, J. (1978), "A User's Guide to the World Oil Project Demand Data Base," MIT Energy Labortory Working Paper MIT-EL 78-016WP. Christensen, L.R., Jorgenson, D.W., and Lau, L.J. (1973), "Conjugate Duality and the Transcendental Logarithmic Production Function," Econometrica , July 1971, pp. 255-256. Diewert, W.E. (1974), "Applications of Duality Theory," in M.D. Intrilligator and D.A. Kendrick (eds.), Frontiers of Quantitative Economics , v. 2, Amsterdam: North-Holland, 1974. Econometrics , (1976), "Exact and Superlative Index Numbers," Journal of 4, 1976, pp. 115-145. Field, B.C. and Grebenstein, C. (1980), "Capital-Energy Substitution in U.S. Manufacturing," forthcoming as note in REStat . Griffin, J.M. (1979), "The Energy-Capital Complementarity Controversy: Progress Report on Reconciliation Attempts," an unpublished memo. A 45 Griffin, J.M. and Gregory, P.R. (1976), "An Intercountry Translog Model of Energy Substitution Process," American Economic Review, vol. 66, Dec. 1976, pp. 847-857. Hirsch, R.B. (1980), "The Capital-Energy Substitution Controversy: Critical Commens on Translog Aggregate Factor Demand Studies," unpublished memo, MIT Energy Laboratory. Houthakker. H.S. (1965), "New Evidence on Demand Elaticities," Econometrica , April 1965, vol. 33, pp. 277-288. Johansen, L. (1972), Prod'jction Functions: An Integration of Micro and Macro, Short-Run and Long-Run Aspects , North-Holland, 1972. Kuh, E., "The Validity of Cross-Sectionally Estimated Behavior Equations in Time Series Applications," Econometrica , 27, 1959, pp. 197-214. (1976), "A Characterization of the Normalized Restricted Profit Function," Journal of Economic Theory , 12^, 1976, pp. 131-163. Lau, L.J. McFadden, D. (1978), "Cost, Revenue and Profit Functions" in Fuss, M. and McFadden, D. (eds.). Production Economics: A Dual Approach to Theory and Applications vol. 1, North-Holland, 19/8. , Nadiri, M.I. and Rosen S., A Disequilibrium Model of Demand for Factors of Production , Columbia University Press, 1973. Pindyck, R.S. (1977), "Interfuel Substitution and the Industrial Demand for Energy: An International Comparison," MIT Energy Labortory Working Paper, MIT-EL 77-026WP, and REStat, vol. 61, no. 2, May 1979, pp. 169-179. Stapleton, David (1980), "Inferring Long term substitution possibilities from cross-section and time-series data", unpublished memeo. University of British Columbia. 46 APPENDIX I Imposing restrictions on KLE translog function with one fixed input (k) : Consider the following translog restricted cost-function. (A.l) In CR = + u ^^ + Y E Z Z) D^. equation is a, In P, J J In P. y ^J i=L,E j=L,E J L + i=L,E ^ + B^ In K + | K 2 In P. + ^ In Y In P ^^ i=L,E If this E .^^^^ + a. In Y + Of. I ^ 6(ln KK In P. p "^ ^^(1^ 2 Y) YY K)^ In K + TT In Y In K ^ directly estimated, there are 16 free parameters that have to be estimated. However, homogeneity of degree one in imposing theoretical restrictions of input prices and the symmetry conditions gives the following linear restrictions: (A. 2) symmetry (A. 3) homogeneity of degree one, y-^. j:Y.j=i:Yij = Yj^ "V" = i, i, J j = L,E c and y]a. = ^7" 1 1 1 For the cost function in equation (1), these constraints can be explicitly written as: (A.4) Yle = YEL \e ^ ^EE " ^EL "^ ^LL Thus in compact notation ^LL = ^EE = "^EL = "^LE (A. 5) Pyl^ = -Pyp (A. 6) p^,^ = -p^^ 47 (A. 7) \ " °E = ^ Imposing restrictions (A. 4) - (A. 8) in the cost function we getl (A. 8) In CR = ttQ + + a^ In Y + In P^ + y^^_{'ir^{P^/P^)f + I + In K P|^|^ I a,_ ln(P|_/P^) + b^ In K + ^ ^^^ y,^k^^" 6^^(ln K)^ + py^ In Y InCPL/P^) ln(P|_/P^) + TT In Y In K. Now the number of free parameters is 10. As a further simplification, we can impose constant returns to scale on the technology by introducing the following linear restrictions: + (A. 9) = B,^ ^Y 1 PyL " ^LK = . ° ^EK = = "*" YyV "" ''YE If - 6^^ = Rewriting equation (A, 9) we get (A. 10) B,^ = 1 - Oy ^LK = -^YL ^YY " " "" '^KK The resulting cost function (now with only 6 free parameters) can be written as (A. 11) (In CR - In P^ - In K) = a^ + ay ln(Y/K) + a^ ^n{P^IP^) - ^ n (ln(Y/K))^ + i y^_^{^MPJP^)f Note the following property, (ln(^))^ = (In x) + PyL ^n{PJ^ - 2 In x ) In (Y/K) In y + (ln(y))' 48 Appendix II Estimating the Restricted Cost Function The estimation method chosen here involves simultaneous estimation of and one of the two share equations. the restricted cost function, CR, Due to the adding-up of property of the share equations, one of the share equations can be left out while still extracting all the information. In general, the system of equations to be estimated can be written as follows, (B.l) In CR = Oq + ay In Y + E B- Z. In ieV * IZE^ij i + 2 I 1" Pi'" "i* Yyy (In Y)^ +^ o^. In p^ ieV ^I>ij i J a^ +X) '" '" "i * iSBij!" i J In Y ^i ^^^. In P. z, 1" z. J In Y In Z- + 1 (B.2) S. =a. ^PYi 1"Y^ LrijlnPj^Z^-jl^Pj^^i j j for all except one ieV. The estimation method should be one that is capable of incorporating both the cross equation parameter restrictions and the specific structural relationships of the error terms. further, I Before pursuing these any will present the simple single fixed factor KLE model considered in this study, thereby, the analysis and description will be much simplified while maintaining the concepts. . 2 {B.3) (In CR - In K - In P^) = oq + ay ln(Y/K) + a^ InCP^/P^) -| it(ln Y/K) 49 Since the share equation is derived by applying Shepard's Lemma to the cost function, the ei^ror terms of the two equations will be related as follows: — —n— from = S, T L 3 In Shepard's Lemma P, By integrating equation (B.4) with respect to In P._ ^g „q^ (8.5) In CR = A^ d(ln P^) = J {a^ + = aj_ In P^_ + + G. In P^^ + function (P^, I ^ ^" ^^ ^^^ y^L ^"(Pl/Pe^ ^YL y^^ In (Pl/P^) In Pl Y, "• "^ ^^^^^'^ PyL ^" ^"^'^^ ^" ^L K) Similarly, by integrating S^ with respect to In P^, we get '^E ~ ^YL ^IL (B.6) In CR = - -^ (1 - a^) In Pf - e In + function P 1" (P|_, ^^L^^E^ Y, ^" """ ^'^^^^ ""^ K) For consistency of equations (B.5), (B.6) with (B.3), (B.7) £(> where plim = e^ ^" (g. . *" ('\/''e ° ^C = and plim np = n-) = The most efficient estimator of the system of equations (B.3) and (B.4) should take into account this explicit relationship between the error terms as well as the cross equation restrictions. Furthermore, if the error terms are assumed to be serially uncorrelated, then by using iterative Zellner estimation, we take into account the cross equation restrictions and the contemporaenous correlation between the error terms. The only loss of efficiency of using Zellner as opposed to FIML is its inability to incorporate the specific error structure. ''e ^l 50 ii >: <? rs r-4 c-i •^r !: CD t"J i: =: L"; vO Vi I'i -O N c; d <- -^ T^. o^ CO «r r-4 c^ ix c- cn lo r-i ^2 <; ^^ -o ^2 •^ cs T^ : !o C< *C C'< O^ »"• C-« >j CD SD r^ =: ;: n ii !! ji i! C-4 ^'' "O fT c-'i •i'- C-- 'T a: !p =; "-^ '' ~O — O ^^ O ^- C- O- C- !> CD OO _C _ .^ _O OOGOC O O O COO o o ?"' '-- '"'' --i I I I i : i= <r ii ;r COOCO^ OOOCOO VD >C SD >G <; vD r^ r- -C -C o OOo I i i ii i 1 i! 5J II ;i J! i'i !t I 2: ii <=: ji ll |:~ OOCO i: OOOOOOCOOOO n s-H—i's-i-sH-r-iT-'. i I i t i I I i i I H > U ii o rn +-> 3 I/) o (U I/) u o>> c cu Q. Q. o OJ 4-> o J- OJ o 1/) <u a: "M CO CS CD r- to r^ > ^^ ^OT-!-r^OOOC^D-G»&- i- I/) .: O c •*— r : i; ! —' n o^n^nm c — ^o ^ o co d^ CO vc t> rc CO iN ^- <? -o IT 10 V-: <^ L"; *? 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I : I I ! i ! •-> t/i il I! i! i! i! -.r a: t-i>ocN^c^rn<c<>fsfo _ ^ i sv r^ -j ro CO rv r^ 5\ rj no r-i so r^ Lo cj >>rt f^^ V: .'.: r;-»-^r >G is. CO >.<^ f^ -c?" c-4 « to >C <T nC cc -q i^; CO <r ... i . r-v •^'- s:; cn so T-: ho rx r.-^ o N~! •<; r~>; o •«5- o m i ; 2^ j5 ! I I 2: <: &; i i i i V V VV V V V li VV V ii cr :t 11 fj i I I if ! i; I ii co id r^ ?~ n ^ C H OO n r. O V 7 V V V V V n^ ^ C ^ r^ \n ci Ci LI rv ^1 f-v -^ Tx -^H LI V-: ?<;; v3 r^ C4 «;- i\ <? >c s: r^ ' CD Tn -C sO CO i\ !^ ^0 CO tS ID j-i n t •; r-j ro f^ c j c-i c < c^4 c i Cvi :i M ?! ! :i: r>i r-.i V V V ii il ii n n o n3,»q o ^ K m T-! T-. !-; !! <: r. CO Dn r^; sd -o vo yj r. rv-jN 0Os CrCrOCG-. V C> CS C^ !! T-! I: Ii -^^ •!-! 1-! v-: T-i tH v-I •j-i a •c- ^: -^r rs CN to cn r^ <^ ^: CO rv ro r-4 f\ so •!-• <^^ tv ix C^ hi Ci CO O^ -r-: C- '^ '^ ^n K; *t> ^"* o i' il i' BASEMIMdu, M/1R3UI9C0 71984 DEC mzyQt DEQ i ^ 'l9B JUL 2 1986 OCT 9191^5 DEC¥?^98t Lib-26-67 ACME BOOKBINDING NOV 1 CO., INC. 1983 100 CAMSRIDGE STREET CHARLESTOWN, MASS. BASEMENT HD28.M414 no.l175- 80 Medoff, James /The role seniority of o "'1 iiiilliiiiiiiiiilililiiii TOAD DDl TTb 3 2flb HD28.M414 no.l176- 80 Kulatilaka. Na/A partial eauilibrmm D*BKS 741444 001.22fi51 001 TTb 22T TOfiD 3 m H028.IV1414 no.ll77- 80 Stoker, Thomas/Aggregation and assumpt —.- -- — D»BKS 741442 fill TOaO 001 TT5 TMO 3 14 no 1178- 80 Matthe/User's manual HD28.M4 Steele. .D»BKS 741456 . . inter for 00.1 3.2 61' 001 TT5 S3b TOflO 3 . HD28.M414 no.ll79- 80 /The influence of group n«B.KS ... <)0^3^ Ralph, Katz 741454 _ 001 TTb 302 TOfiO HD28.WI414 no.ll80- 81 Meldman, Jef fr/American expectations D*BKS 742205 om ooa loflo 3 ^ HD28.IVI414 no.ll81- 81 Kochan, Thomas/The effects of 0»BKS 742009 I mil mil II I iijii TOflO 3 m o Ofl.jlW.fl'f 3M collecti 00132627 lii iiil ill nil iliii II i iiti ii ill DDl TTS ?b7 HD28.M414 no.ll82- 81 Roberts, Edwar/ls effect! licensing an D«BKS 742011 00132652 iiiiil 3 TOaO 001 TTb 2MS HD28.IVI414 Lattin, 74200"6 3 no.ll83- James /T 81 scaling - - D*BKS 2G11 TDaO DDl TTS MbO