Does Why the Cyclical Behavior of Real Wages Change Over Time?
Kevin X. D. Huang Kansas City Fed CIRPEE (Canada) [e-mail] Zheng Liu Emory University CIRPEE (Canada) [e-mail] Revised: December 2003 Louis Phaneuf University of Quebec at Montreal CIRPEE (Canada) [e-mail]
Abstract The cyclical behavior of real wages has evolved from mildly countercyclical during the interwar period to modestly procyclical in the postwar era. This paper presents a general equilibrium business cycle model that helps explain the evolution. In the model, changes in the real wage cyclicality arise from interactions between nominal wage and price rigidities and an evolving input-output structure. (JEL E24, E32, E52).
The authors are grateful to Henning Bohn, Robert Chirinko, Todd Clark, Russell Cooper, Charles Evans,
Peter Ireland, Robert King, Sharon Kozicki, Tommaso Monacelli, Plutarchos Sakellaris, Fabio Schiantarelli, Shouyong Shi, Frank Smets, Jonathan Willis, and seminar participants at Boston University, Emory University, Tufts University, the University of California at Santa Barbara, the European Central Bank, the Federal Reserve Bank of Atlanta, the Federal Reserve Bank of Kansas City, the 2001 Midwest Macro Meeting, the 2001 SED Annual Meeting, and the Econometric Society 2002 Winter Meeting for helpful comments. The comments and suggestions from two anonymous referees are especially useful in improving the exposition in the paper. Phaneuf acknowledges nancial support from FQRSC and SSHRC. The views expressed in the paper are those of the authors and they do not represent the views of the Federal Reserve Bank of Kansas City or the Federal Reserve System.
I. Introduction Empirical studies suggest that the cyclical behavior of real wages in the United States has evolved over time. It has changed from mildly countercyclical during the interwar period to modestly procyclical during the post World War II period. This general pattern holds regardless of the specic choices of data frequency, variable denitions, or detrending methods (see the next section). In this paper, we provide a theory that helps understand the historical evolution of real wage cyclicality. Our theory suggests that changes in the cyclical behavior of real wages arise from interactions between nominal wage and price rigidities and an evolving input-output structure in the U.S. economy. Our explanation does not rely on a story of mixtures of shocks. According to that story, demand shocks have led to countercyclical real wages during the interwar period, as standard Keynesian models would predict; and supply shocks have given rise to procyclical real wages during the postwar period, in the spirit of real business cycle models. The oil price shocks that occurred in the 1970s are often viewed as a factor that has led to procyclical real wages during the postwar period. We do not nd this explanation appealing. First, while empirical studies suggest that oil price shocks may have been an important contributing force that drives postwar U.S. business cycles, they do not provide support for the view that oil price shocks have triggered the switch in the sign of the correlation between measures of real wages and aggregate output. Susanto Basu and Alan M. Taylor (1999a) present evidence that U.S. real wages have switched from being countercylical to being procyclical from the interwar period (1919-1939) to the Bretton Woods period (1945-1971), a period prior to the onset of the major oil price shocks in the 1970s. Indeed, real wages remain procyclical even when the period from December 1973 through June 1980 is excluded from the entire postwar sample [e.g., Christopher Hanes (1996)].1 Second, several recent studies cast serious doubt on the abilities of business cycle theories that assign a prominent role to exogenous variations in technologies in explaining the postwar business cycle uctuations, especially the labor market uctuations [e.g. Julio J. Rotemberg and Michael Woodford (1996), Basu (1998), Basu, John Fernald
1
The case for oil shock seems to be further weakened by the observation that the price of crude oil has
remained relatively stable until 1973 [e.g., Kevin D. Hoover and Stephen J. Perez (1994) and Charles A. Fleischman (1999)]. James D. Hamilton (1983) argues that oil shocks have Granger-caused some of the pre-1970 recessions in the U.S., but the cyclical eects of these shocks, as he shows, became much stronger during the 1970s.
2
and Miles S. Kimball (1998), Jordi Gali (1999), and Neville Francis and Valerie A. Ramey (2002)]. Third, as we will discuss in the next section, a number of studies shows that monetary contractions have triggered a rise in real wages in the interwar period, especially during the Great Depression, but a fall in real wages along with output in the postwar era. This changing cyclical pattern of real wages driven solely by monetary shocks can hardly be explained by a theory that relies on dierent mixtures of shocks. These considerations, especially the third, lead us to focus on a business cycle model driven solely by demand shocks. Specically, we develop a dynamic general equilibrium model that features staggered price and staggered wage contracts, along with a roundabout input-output structure in the spirit of Basu (1995).2 The linchpin of our analysis, as suggested by historical evidence produced by Hanes (1996, 1999) and corroborated by Basu and Taylor (1999a, b), is that more-processed products have become increasingly important in U.S. aggregate output from the interwar period to the postwar period, indicating increasing roundabout production throughout the twentieth century. In our model, this ascending sophistication of the inputoutput structure takes the form of a rising share of intermediate inputs in production from the interwar period to the postwar period. We nd that, as the share of intermediate inputs grows from a range plausible for the interwar period into a range plausible for the postwar period, the real wage switches from being mildly countercyclical to being modestly procyclical. This switch of real wage cyclicality is accompanied by changes in the business cycle properties of U.S. output across the two periods, which arise endogenously from the model and are consistent with the U.S. data. In general, our model generates reasonable-looking business cycle statistics under calibrated parameters for both the interwar period and the postwar era.3 The three main features of the model play an essential role in generating these results. For instance, in the case with only staggered price contracts or only staggered wage contracts, the
2
While the input-output table of the Bureau of Economic Analysis apparently features both horizontal
roundabout and vertical in-line production, Basu (1995, pp. 514-515) observes that, Input-output studies certainly do not support the chain-of-production view; even the most detailed input-output tables show surprisingly few zeros. Empirically, the biggest source of any industrys inputs is usually itself: that is, the diagonal entries of input-output matrices are almost always the largest elements of each column (see Bureau of Economic Analysis, 1984). This seems to lend credence to the view of roundabout rather than in-line production. 3 To examine the historical change in the cyclical behaviors of real wages, we focus on the eects of changes in the sophistication of the input-output structure while holding all other changes in the structure of the economy constant. This is not our interpretation of what has actually transpired over the course of the history, but rather we view it as the best way to isolate the impact of one particular change.
3
real wage is either strongly procyclical or strongly countercyclical, regardless of the share of intermediate inputs. With both staggered price and staggered wage contracts of similar lengths, a scenario that seems plausible in light of the evidence surveyed by John B. Taylor (1999), the real wage is countercyclical if there is no or a small share of intermediate inputs, because the price level is less sticky than the nominal wage index due to exibility in the capital rental rate.4 But, as the share of intermediate inputs grows larger, the rigid intermediate input price becomes a more signicant component of marginal cost, and as a result the price level becomes more rigid, making real wages more procyclical. The rising share of intermediate inputs also generates endogenous stickiness in nominal wages through the eect of substitutions between labor and intermediate inputs, preventing the real wage from becoming perfectly correlated with real GDP even when the share of intermediate inputs approaches one. Thus, the real wage switches from mildly countercyclical to acyclical, and then to moderately procyclical, as the share of intermediate inputs grows from a range plausible for the interwar period into a range plausible for the postwar period. II. The Evolution of the Cyclical Behavior of Real Wages: Some Evidence Several studies suggest that the cyclical behavior of real wages have been changing over time. The evidence obtained based on dierent types of data, sample periods, real wage denitions, detrending methods, and estimation procedures helps reach the following consensus: (i) measures of unconditional correlations between real wages and output reveal that real wages have changed from being mildly countercyclical during the interwar period to being modestly procyclical during the postwar period; (ii) monetary contractions have caused real wages to rise during the interwar period, especially in the Great Depression, while they have typically led to a fall in real wages along with output in the postwar era. We consider rst changes in the cyclical behavior of real wages across the two sample periods from the perspective of unconditional correlations between real wages and output. An insightful account of such changes is provided by Ben Bernanke and James L. Powell (1986), who examine the cyclical properties of real wages at both the frequency domain and the time domain for the periods 1923-1939 and 1954-1982, and nd evidence that real wages have become increasingly procyclical during the postwar period. Bernanke and Powells (1986)
4
This nding stands in contrast to the conventional view articulated by, for example, Olivier J. Blanchard
(1986) and Robert J. Barro and Herschel I. Grossman (1971), who abstract from capital accumulation.
4
study is important for yet another reason. One could argue that the sectoral composition used by the Bureau of Economic Analysis to measure output has changed from the interwar period to the postwar period. If this were the case, the observed switch in the cyclical behavior of real wages could have simply reected changes in sectoral composition. Studies using aggregate data cannot directly confront this issue.5 Bernanke and Powell (1986) employ industry level data that control for the sectoral composition bias and nd that there has been a marked dierence in the cyclical behavior of real wages from the interwar to the postwar period. Basu and Taylor (1999a) also oer evidence that the cyclical behavior of real wages have changed from the interwar period to the postwar period. Using aggregate data detrended by the band-pass lter proposed by Marianne Baxter and Robert G. King (1995) (i.e., the BK lter), they nd that the correlation between real wages and aggregate output in the U.S. economy has changed from 0.444 in the interwar period (1919-1939), to 0.381 during the Bretton Woods period (1945-1971), and further to about 0.503 during the more recent period of oating exchange rates (1972-1992). Thus, the switch from countercyclical to procyclical real wages from the interwar to the postwar period have already taken place before the onset of major oil price shocks, suggesting that forces other than oil shocks have triggered the switch.6 Available evidence also suggests that real wages have responded dierently to monetary shocks during the interwar and the postwar periods. For the interwar period, Barry Eichengreen and Jerey Sachs (1985, 1986) and Bernanke and Kevin Carey (1996) examine multicountry data and use money supplies and aggregate demand shifters as instruments to identify aggregate supply relations. They nd that real wages were countercyclical during the interwar
5
Robert C. Chirinko (1980) emphasizes the sectoral composition bias of real wage cyclicality in the postwar
U.S. economy. 6 Hanes (1996) provides corroborating evidence, based on U.S. data detrended by the Hodrick-Prescott lter (i.e., the HP lter), on the switch of sign in the correlation between real wages and aggregate output from the interwar sample (1923-1941) to the postwar period (1947-1990). Several other studies based on dierent sources of data and empirical methods have shown that real wages in the postwar U.S. economy are procyclical. For example, Mark Bils (1985) nds strongly procyclical real wages using disaggregated panel data collected by the National Longitudinal Survey from 1966 to 1980; Gary Solon, Robert Barsky, and Jonathan A. Parker (1994) control for a composition bias in the wage data and corroborate Bilss ndings using data from the Panel Study of Income Dynamics (PSID); Kydland (1995) reports that the contemporaneous correlation between real wages and output is about 0.35 using HP-ltered postwar U.S. data; and Wouter J. den Haan and Steven W. Sumner (2002) use the correlation coecients of VAR forecast errors at dierent forecasting horizons, a measure of comovement originally proposed by den Haan (2000), and nd a signicant positive correlation between real wages and aggregate output for the G7 countries over the period from February 1965 to December 2001.
5
period and that monetary shocks were a central driving force of this result. Bernanke and Carey (1996) argue on the basis of their ndings for a dismissal of explanations of the outputreal wage relationship during the period from 1929-1936 that do not involve nominal shocks and nonneutrality of money. After all, adverse technology shocks should induce low, not high real wages.7 Several studies have also examined the response of real wages to monetary shocks during the postwar period. For instance, Lawrence J. Christiano, Martin Eichenbaum and Charles Evans (1997) study a vector autoregression system (VAR), to which they impose short-run restrictions to identify monetary policy shocks, and nd that contractionary monetary shocks typically lead to a fall in real wages along with output. Edward N. Gamber and Frederick L. Joutz (1993) use an alternative identication approach by imposing long-run restrictions in a VAR system and nd that monetary shocks, and demand shocks in general, tend to generate procyclical real wages during the postwar period.8 Using a narrative approach developed by Christina Romer and David Romer (1989), Marvin J. Barth III and Ramey (2001) nd evidence of procyclical real wages following contractionary monetary policy actions in the postwar U.S. economy. In sum, the evidence suggests a general pattern of the cyclical behavior of real wages: it has evolved from mildly countercyclical during the interwar period to modestly procyclical in the postwar era. Further, contractionary monetary shocks were typically followed by a rise in real wages in the early part of the sample and by a decline in real wages in the later part. The switch in the cyclical behavior of real wages has occurred at a time when oil price shocks were virtually absent and when there has been an increase in roundabout production in the U.S. economy. III. The Model
7
Michael D. Bordo, Christopher J. Erceg and Charles L. Evans (2000) present evidence consistent with this
nding. Through simulating a sticky wage model, they nd that contractionary monetary shocks led to an increase in real wages during the downturn phase of 1929-1933 in the U.S., and monetary shocks accounted for between 50 and 70 percent of the decline in real GNP at the Depressions trough in the rst quarter of 1933. 8 One study that arrives at a somewhat dierent result is that of Fleischman (1999), who imposes long-run restrictions. His point estimates suggest a countercyclical response of real wages to aggregate demand shocks in the postwar U.S. data. However, the estimated correlations between real wages and output are so imprecise that he concludes that in response to aggregate demand shocks, real wages and output are essentially uncorrelated. (p.24)
6
The economy is populated by a large number of households, each endowed with a differentiated labor skill indexed by i [0, 1]; and a large number of rms, each producing a dierentiated good indexed by j [0, 1]. There is a government conducting monetary policy. In each period t, a shock st is realized. The history of events up to date t is denoted by st (s0 , , st ), with probability (st ). The initial realization s0 is given. Denote by L(st ) a composite of dierentiated labor skills {L(i, st )}i[0,1] such that L(st ) =
/(1) 1 t (1)/ di , 0 L(i, s )
and by X(st ) a composite of dierentiated goods {X(j, st )}j[0,1] where (1, ) and (1, ) are the elasticity
so that X(st ) =
/(1) 1 t (1)/ dj , 0 X(j, s )
of substitution between the skills and between the goods, respectively. The composite skill and the composite good are both produced in an aggregation sector that is perfectly competitive. The demand functions for labor skill i and for good j resulting from the optimizing behavior in the aggregation sector are given by (1) W (i, st ) L (i, s ) = W (st )
d t
L(s ),
t
P (j, st ) X (j, s ) = P (st )
d t
X(st ),
where the wage rate W (st ) of the composite skill is related to the wage rates {W (i, st )}i[0,1] of the dierentiated skills by W (st ) =
1/(1) 1 t 1 dj . 0 P (j, s ) 1/(1) 1 t 1 di , 0 W (i, s )
and the price P (st ) of the
composite good is related to the prices {P (j, st )}j[0,1] of the dierentiated goods by P (st ) =
The dening feature of the model is that, while the composite skill serves only as an input for the production of each dierentiated good, the composite good can serve either as a nal consumption or investment good, or as an intermediate production input. The production of a type j good requires capital, labor, and intermediate inputs, with the production function given by (2) X(j, st ) = (j, st ) K(j, st ) L(j, st )1
1
F,
where (j, st ) is the input of intermediate goods, K(j, st ) and L(j, st ) are the inputs of capital and the composite skill, and F is a xed cost that is identical across rms. The parameter (0, 1) measures the elasticity of output with respect to intermediate input, and the parameters (0, 1) and (1 ) are the elasticities of value-added with respect to capital input and labor input, respectively. Each rm is a price-taker in the input markets and monopolistic competitor in the product market, where it can set a price for its product, taking the demand schedule in (1) as given. 7
At each date t, a fraction 1/Np of the rms chooses new prices after the realization of the shock st . Once a price is set, it remains eective for Np periods. All rms are divided into Np cohorts based on the timing of their pricing decisions. A rm j in the cohort that can set a new price at date t chooses P (j, st ) to maximize its prot
t+Np 1
D(s |st ) P (j, st )X d (j, s ) V (X d (j, s )) ,
=t s
where, for t, D(s |st ) denotes the price of a dollar at s in units of dollars at st , and V (X d (j, s )) denotes the cost of producing X d (j, s ), equal to V (s )[X d (j, s ) + F ], with V (s ) denoting the marginal cost of production at s . Solving the prot-maximization problem yields the optimal pricing decision rule (3) P (j, st ) = 1
t+Np 1 t d =t s D(s |s )X (j, s )V (s ) , t+Np 1 t d =t s D(s |s )X (j, s )
which says that the optimal price is a constant markup over a weighted average of the marginal costs for the periods in which the price will be eective. Solving the rms cost-minimization problem yields the marginal cost function: (4)
1 1 V (s ) = P (s ) [Rk (s ) W (s ) ] ,
where is a constant determined by and . The (conditional) demand functions for intermediate input and for primary factor inputs in producing X d (j, s ) derived from cost-minimization are given by (5) (6) and (7) L(j, s ) = (1 )(1 ) V (s )[X d (j, s ) + F ] . W (s ) (j, s ) = V (s )[X d (j, s ) + F ] , P (s ) V (s )[X d (j, s ) + F ] , Rk (s )
K(j, s ) = (1 )
Even if a rm cannot choose a new price at a given date, it would still need to choose the inputs of the intermediate good, the capital, and the composite labor to minimize production cost. Each household i has a subjective discount factor (0, 1) and a utility function
(8)
t=0 st
t (st ) ln C (i, st )) 8
L(i, st )1+ 1+
,
where C (i, st ) [bC(i) + (1 b)(M (i)/P ) ]1/ is a CES composite of consumption good and real money balances, and L(i, st ) is the households hours worked. The budget constraint facing the household in event history st is (9) P (st )Y (i, st ) +
t d st+1 t
D(st+1 |st )B(i, st+1 ) + M (i, st )
W (i, s )L (i, s ) + Rk (st )K(i, st1 ) + (i, st ) + B(i, st ) + M (i, st1 ) + T (i, st ), where B(i, st+1 ) is a nominal bond that represents a claim to one dollar in event st+1 and costs D(st+1 |st ) dollars at st , W (i, st ) is a nominal wage for is labor skill, Ld (i, st ) is a demand schedule for type i labor specied in (1), Rk (st ) is a nominal rental rate on capital, K(i, st1 ) is is beginning-of-period capital stock, (i, st ) is its share of prots, and T (i, st ) is a lump-sum transfer it receives from the government. The composite good Y (i, st ) can be either consumed or invested, and if net investment is positive, an adjustment cost will also be incurred. Thus (10) Y (i, st ) = C(i, st ) + K(i, st ) (1 )K(i, st1 ) + (K(i, st ) K(i, st1 ))2 , K(i, st1 )
where (0, 1) is a capital depreciation rate and the quadratic term is a capital adjustment cost with a scale parameter > 0. Each household is a price-taker in the goods market and a monopolistic competitor in the labor market, where it sets a nominal wage for its dierentiated labor skill, taking the demand schedule (1) as given. In each period t, upon the realization of shocks st , a fraction 1/Nw of the households chooses new wages. These wages, once set, remain eective for Nw periods. All households are divided into Nw cohorts based on the timing of their wage decisions. Each household maximizes (8) subject to (10), (10), and a borrowing constraint B(i, st+1 ) B, for some large positive number B. The initial conditions on bond, money, and capital are given. At date t, if a household i can set a new wage, then the optimal choice of its nominal wage is given by (11) W (i, st ) = 1
t+Nw 1 t d =t s D(s |s )L (i, s )M RS(i, s ) , t+Nw 1 t d =t s D(s |s )L (i, s )
where M RS(i, s ) denotes the marginal rate of substitution between leisure and income. Thus the optimal wage is a markup over a weighted average of the MRS during the periods in which the wage will remain eective. All households need to make decisions on consumption, investment, money balances, and bond holdings, and we have used the standard rst order condition for bond holdings in deriving (11). 9
Our purpose is to establish a link between the increasing sophistication of input-output connections and the evolving nature of the cyclical behaviors of real wages over time in the U.S. economy. For reasons stated in the introduction, we focus on demand-driven business cycle uctuations. In what follows, we examine the dynamic eects on real GDP and the real wage of a monetary policy shock, which is a particular type of aggregate demand shock.9 In the model economy, monetary policy is conducted via a lump-sum transfer so that
1 t 0 T (i, s )
= M s (st ) M s (st1 ). Money stock grows at a rate (st ), which follows a stationary ln (st ) = ln (st1 ) + t ,
stochastic process given by (12)
2 where 0 < < 1 and t is a white noise process with a zero mean and a nite variance .
An equilibrium for this economy consists of allocations C(i, st ), K(i, st ), B(i, st+1 ), M (i, st ), and wage W (i, st ) for household i, for all i [0, 1], allocations (j, st ), K(j, st ), L(j, st ), and price P (j, st ) for rm j, for all j [0, 1], together with prices D(st+1 |st ), P (st ), Rk (st ),and W (st ), that satisfy the following conditions: (i) taking the wages and all prices but its own as given, each rms allocations and price solve its prot maximization problem; (ii) taking the prices and all wages but its own as given, each households allocations and wage solve its utility maximization problem; (iii) markets for money, bonds, capital, the composite labor, and the composite good clear; (iv) monetary policy is as specied. We suppose that there are (implicit) state-contingent nancial contracts that make it possible to insure each household against the idiosyncratic income risk that may arise from the asynchronized wage adjustments. In particular, we follow the literature and assume that such nancial arrangements ensure that equilibrium consumption, investment, and holdings of real money balances are identical across households, although nominal wages and hours worked may dier.[e.g., Rotemberg and Woodford (1997) and Christiano, et al. (2001)].10 Under this assumption, we have Y (i, st ) =
1 0 Y
9
1 0 Y
(i, st )di = Y (st ) for all i and for every st , where
Y (st ) denotes real GDP. Given this relation, along with (5), the market clearing condition (i, st )di +
1 t 0 (j, s )dj
= X(st ) for the composite good implies that equilibrium real GDP
In a unreported experiment, we nd that the results are robust when we consider an alternative form of
aggregate demand shocks, in particular, shocks to nominal GDP. 10 This assumption is made for analytical convenience. In the appendix, we present an alternative model structure (essentially a reinterpretation of the baseline model), which produces identical equilibrium dynamics as in the baseline model without requiring such implicit nancial arrangement for the purpose of aggregation.
10
is related to gross output by (13) where G(st ) V (st ) Y (st ) = X(st ) t G(st )X(st ) + F , P (s )
1 t t 0 [P (j, s )/P (s )] dj
captures the price-dispersion eect of staggered price con1 d t 0 K (j, s )dj
tracts. Meanwhile, the market clearing conditions for capital and
1 t 0 L(j, s )dj
=
1 t1 )di 0 K(i, s
K(st1 )
= L(st ) for the composite skill, along with (6)-(7), imply that
equilibrium aggregate capital stock and composite skill are related to gross output by (14) (15) K(st1 ) = (1 ) V (st ) G(st )X(st ) + F , Rk (st )
V (st ) L(st ) = (1 )(1 ) t G(st )X(st ) + F . W (s )
Equations (13), (14), (15), the money market clearing condition, together with the price-setting equation (3) and the wage-setting equation (11), characterize an equilibrium. IV. Parameter Calibration The parameters to be calibrated include the subjective discount factor , the preference parameters b, , and , the technology parameters and , the elasticity of substitution between dierentiated goods and between dierentiated labor skills , the capital depreciation rate , the adjustment cost parameter , the duration of nominal contracts Np and Nw , and the monetary policy parameters and .11 We also need to calibrate the steady state ratio of the xed cost to gross output F/X. The calibrated values are summarized in Table 1. A period in our model corresponds to a quarter of a year. Following the standard business cycle literature, we set = 0.99, = 2, and = 0.025, so that, in a steady state, the annualized real interest rate is 4 percent, the intertemporal elasticity of labor hours is 0.5, and the annual capital depreciation rate is 10 percent. To assign values for b and , we use the equilibrium money demand equation log M (st ) P (st )
st+1
=
1 b log 1 1b
1
+ log(C(st ))
1 log 1
R(st ) 1 , R(st )
where R(st ) =
D(st+1 |st )
is the gross nominal interest rate. A regression of con-
sumption velocity on nominal interest rates, using U.S. M1 data from quarter one of 1959 to
11
The parameter in the utility function does not aect equilibrium dynamics (in the log-linearized equilib-
rium system) and thus we do not need to assign a particular value to it.
11
quarter four of 1999, results in b = 0.998 and = 1.76. The implied interest elasticity is 0.36, with a standard error of 0.04, similar to those obtained by V.V. Chari, et al. (2000) and Robert E. Lucas, Jr. (1988).12 We calibrate the capital adjustment cost parameter so that the model generates a standard deviation of investment 2.78 times as large as that of real GDP, in accordance with the evidence in Chari, et al. (2002).13 The parameter determines the steady-state markup of prices over marginal cost, with the markup given by p = /( 1). Recent studies by Basu and Fernald (1997a, 2000) suggest that the value-added markup, controlling for factor capacity utilization rates, is about 1.05; whereas without any utilization correction, the value-added markup is about 1.12. Some other studies suggest a higher value-added markup of about 1.2 (without corrections for factor utilization) [e.g., Rotemberg and Woodford (1997)]. Since we do not focus on variations in factor utilization, in light of these studies, we set = 11 so that p = 1.1.14 The parameter measures the elasticity of substitution between dierentiated labor skills. We set = 3 based on the micro-evidence produced by Peter Grin (1992, 1996), implying that a one-percent rise in a households nominal wage relative to the wage index leads to a three-percent fall in its employed hours relative to aggregate employment. Given the calibrated value of (or p ), we set the steady state ratio of the xed cost to gross output F/X equal to p 1 = 0.1, so that the steady state prots for rms are zero (and there will be no incentive to enter or exit the industry in the long-run). With zero economic prot, the parameter corresponds to the share of payments to capital in total value added in the National Income and Product Account (NIPA). The implied value of is then 0.4, in
12
The theoretically correct measure of money should be non-interest-bearing instruments, that is, the mon-
etary base. Since our model nests a few popular models in the literature as special cases (e.g., Chari, et al. (2000) and Kevin X.D. Huang and Zheng Liu (2002)), and these authors use M1 to calibrate their money demand parameters, we also use M1 in our baseline calibration to have our model better connected to this strand of literature. The main results are not sensitive to the use of M0 in place of M1 (not reported). 13 The reason that we include capital adjustment costs is to get the volatilities of investment and output right [e.g., Chari, et al. (2000)]. The patterns of real wage cyclicality is not sensitive to the inclusion of adjustment costs. 14 Basu and Fernald (2000) also note that, in the presence of intermediate input, if the intermediate input price diers from gross output price, then the gross-output markup (corresponding to /( 1) in our model) is no larger than the value-added markup. We have also experimented with other values of p and nd that the main results do not change for any given value of (not reported). Yet, as we will make clear below, the markup parameter does aect our calibration of .
12
line with the value used in the standard real business cycle literature [e.g., Thomas F. Cooley and Edward C. Prescott (1995)].15 The parameter measures the share of payments to intermediate input in total production cost (i.e., the cost share). With markup pricing, it equals the product of the share of intermediate input in gross output (i.e., the revenue share) and the steady state markup. We rely on two sources of data to calibrate the value of for the postwar U.S. economy. The rst source is the study by Dale Jorgenson, et al. (1987), who nd that the revenue share of intermediate input in total manufacturing output is 50 percent or more for the period 1947-1979. Based on this study, Basu (1995) views 0.5 as a lower bound for . The second source is our direct calculation using data in the 1997 Benchmark Input-Output Tables of the Bureau of Economic Analysis (BEA 1997). In the Input-Output Table, the ratio of total intermediate to total industry output for the manufacturing sector is 0.68. Thus, given that the calibrated markup is p = 1.1, the cost share of intermediate input should lie in the range between 0.55 and 0.74. We take = 0.7 as a benchmark for the postwar U.S. economy.16 Unlike the postwar period, there seems to be little direct evidence on the share of intermediate input in manufacturing output during the interwar period. Historical evidence suggests that the input-output structure in the U.S. economy has become more sophisticated from the interwar period to the postwar period [e.g., Hanes (1996)]. In the early years, a households consumption basket was primarily made up of relatively unnished goods. Since then, there
15
Much empirical evidence suggests that prot rates are close to zero [e.g., Rotemberg and Woodford (1995)
and Basu and Fernald (1997b)]. We are grateful to an anonymous referee who suggests the inclusion of the xed cost so that the economic prot is zero in the long-run and can be calibrated using consistent data in the NIPA. 16 BEAs input-output table suggests that industries in the U.S. economy are inter-connected through both roundabout and vertical in-line production, while our model has roundabout production only. In this sense, the parameter summarizes the importance of both roundabout and in-line production. Note that changes in vertical integration may change the share of intermediate inputs. This is consistent with our model as long as prices are sticky between rms, but transfer pricing is exible within each rm.
13
has been more roundabout production before a typical good enters the nal consumption basket.17 This evidence suggests a general tendency of increased sophistication of the input-output structure in the U.S. economy, that is, an increase in over time. To calibrate a value of for the interwar period, we have also looked up John W. Kendricks (1961) work. Kendrick reports gross output and value added for several key sectors in the prewar period, but all numbers are indexes with 1929 being 100, except for farm output in Table B-1 (p. 347), where he reports the constant 1929 dollar values. Using this information, we can directly calculate the share of intermediate input in gross farm output for the interwar period: it lies in the range between 0.18 and 0.22 in the period 1919-1937. In the postwar period, according to BEA (1998), the corresponding share has risen to around 0.6. Although this information does not help us pin down a specic range of the share parameter in the manufacturing sector during the interwar period, it does conrm the general tendency that the input-output structure has become more sophisticated over time. In light of the limited evidence, it seems reasonable to consider a value of between 0.3 and 0.5 for the interwar period, when the input-output structure was relatively simple. We take = 0.4 as a benchmark for the interwar period in the U.S. economy. Empirical evidence suggests that the lengths of nominal contracts are roughly the same for both prices and nominal wages: they both last for about one year [see, for example, the comprehensive survey by Taylor (1999)]. Thus, we set Np = 4 and Nw = 4 as the benchmark values, so that, in each quarter, a fraction 1/4 of rms and households can adjust prices and wages; and once adjusted, they remain eective for four quarters.18
17
Hanes (1996) reports that the share of crude material inputs (such as farm, shery and mineral products)
in nal output in the United States has fallen from 26 percent to only 6 percent from the beginning of the twentieth century to the end of the 1960s. He also reports that, according to household budget surveys, the share of consumption expenditure on food (excluding restaurant meals) has fallen from 44.1 percent at the turn of the twentieth century to 11.3 percent in 1986, while the share of the budget category Other that includes many complex goods such as automobiles has increased steadily from 17 percent to 45.8 percent over the same period. 18 In an unreported experiment, we vary the lengths of nominal contracts and nd that, as long as there is no signicant dierence in the durations of price and wage contracts, the real wage will change from modestly countercyclical for in a range plausible for the prewar era to weakly procyclical as grows into a range plausible for the postwar period.
14
Finally, we set the serial correlation parameter of money growth rate to 0.68 and the standard deviation of the innovation term in the money growth process to 0.008, based on M1 data in the postwar U.S. economy.19 V. Explaining the Cyclical Behavior of Real Wages Empirical evidence reveals that real wages in the U.S. economy have switched from being mildly countercyclical during the interwar period to being mildly procyclical in the postwar era. At the same time, the input-output structure in the economy has become increasingly sophisticated. In this section, we explore the apparent connections between the historical evolution of the cyclical properties of real wages and the evolving input-output structure. We do so by considering three stylized models, each a special case nested by the baseline model, all with intermediate goods but with dierent sources of nominal rigidities. We investigate what mixture of nominal and real rigidities can account for the observed evolving nature of real wage cyclicality, while at the same time generate plausible output dynamics. A. Staggered Price-Setting The rst model we consider features staggered price-setting and an input-output structure, with exible nominal wage decisions. In the absence of intermediate goods, it is well known that a sticky price model tends to generate strongly procyclical real wages in response to aggregate demand shocks [e.g., Rotemberg (1982)]. With sticky prices, an expansionary aggregate demand shock leads to higher real output and consumption. Meanwhile, the higher demand for goods pushes up the demand for labor input. Since nominal wages are exible, the optimal wage-setting equation (11) implies that the real wage is a constant markup over the marginal rate of substitution (MRS) between leisure and consumption. With higher labor demand, the marginal disutility of working rises; with higher consumption, the marginal utility of consumption falls. In consequence, the MRS rises, so does the real wage. Adding intermediate goods in production does not dampen the increase in the real wage. As the share of intermediate goods rises, price adjustments become more sluggish and thus the responses of
19
As we show in the next section, main the results are not sensitive if we calibrate the money shock process
using prewar M1 data [see Section V(D)].
15
consumption and labor input become stronger. It follows that the MRS and therefore the real wage remain strongly procyclical. Figure 1 plots the impulse responses of real GDP and the real wage following a one-percent shock to the money growth rate. The responses of the two variables apparently display very similar patterns, suggesting high cross-correlations between the two variables. Figure 4, which plots the contemporaneous cross-correlations between the real wage and output, conrms that this is indeed the case: With the calibrated money growth process and staggered price-setting, the correlation is strongly positive and is insensitive to changes in the share of intermediate input. Thus, staggered price-setting alone is incapable of generating the observed switch of real wage cyclicality, with or without intermediate input. The strong procyclicality of real wage is accompanied by a lack of output persistence. Since the real wage is part of the real marginal cost, a strongly procyclical real wage forces rms to pass the increase in their labor cost to an increase in prices whenever they can set new prices. With no intermediate goods, the price level will rise completely as soon as all rms nish adjusting prices and thus there is no output persistence. The incorporation of intermediate input in production reduces the share of labor cost and thus increases the price level rigidity and output persistence. Figure 1 conrms this intuition: with no intermediate goods, the response of real GDP does not last beyond the initial duration of the price contracts; as rises, the response of real GDP becomes more persistent, but the quantitative dierence is small. B. Staggered Wage-Setting The second model we consider features staggered wage-setting and an input-output structure, with exible price adjustments. Figure 2 displays the responses of real GDP and the real wage for various values of . Evidently, the model here generates more output persistence than the model with staggered prices. But it predicts strongly countercyclical movements of the real wage. This is because prices are a constant markup over the marginal cost, and the marginal cost, being composed of the rigid nominal wage index and the exible nominal rental rate on capital, changes more quickly than does the wage index. Incorporating intermediate goods does not alter the real wage behavior, nor does it help magnify output persistence. Since pricing decisions are not staggered here, all rms set the same price in a symmetric equilibrium. Thus, the optimal pricing equation is the same with or without intermediate goods. 16
This intuition becomes more transparent when we look at the optimal pricing decision rule, which is a special case of equation (3) and is given by (16) P (j, st ) = t k t (1) t (1)(1) P (s ) R (s ) W (s ) , 1
where we have plugged in the unit cost function from (4). With synchronized pricing decisions, P (j) = P for all j, and thus the pricing equation (16) reduces to (17) P (st ) = k t t 1 R (s ) W (s ) , 1
which is formally identical (up to a constant) to the pricing equation in the model with staggered wage contracts but without intermediate goods [e.g., Huang and Liu (2002)].20 Thus a staggered wage model, with or without intermediate goods, generates substantial output persistence and strongly countercyclical responses of the real wage following a monetary shock. We also compute the contemporaneous cross-correlations between the real wage and real GDP in the model with staggered wage-setting under calibrated money growth shocks. As is evident from Figure 4, the real wage is strongly negatively correlated with real GDP, and the correlations are not sensitive to the values of , conforming the near mirror-image responses of the two variables displayed in Figure 2. C. Staggered Price-Setting and Staggered Wage-Setting Since real wages are procyclical under sticky prices and countercyclical under sticky wages, a common view is that having both pricing and wage decisions staggered should imply acyclical real wages [e.g., Blanchard (1986) and Barro and Grossman (1971)]. We nd here that this is generally not the case in a dynamic general equilibrium model with capital accumulation. As shown in Figure 3 and Figure 4, in the absence of intermediate input, the real wage is countercyclical even when both pricing and wage-setting decisions are staggered with similar contract durations. The reason is that, with labor and capital both being variable factors in production, the marginal production cost records both the rigid wage index and the exible capital rental rate, so that it varies more than the wage index, implying a more variable price level as well.21 With intermediate input in production, the real wage becomes less
20
With staggered wage-setting alone, the share of intermediate input only aects the steady state values, but
not deviations from the steady state. 21 In a model like this (with capital accumulation but without intermediate input), one could still obtain the Blanchard-Barro-Grossman result by varying the durations of price and wage contracts. But there seems to be no evidence that these contract durations systematically dier.
17
countercyclical or more procyclical. In particular, Figure 4 shows that the correlation between the two variables turns from negative when is small to positive when is suciently large. As grows from the interwar benchmark value of 0.4 to the postwar benchmark value of 0.7, the correlation changes from 0.51 to 0.45.22 In this sense, the model with both staggered price-setting and staggered wage-setting, along with the roundabout input-output structure, is able to explain the observed patterns of real wage cyclicality: it switched from mildly countercyclical during the interwar period when the input-output structure was relatively simple to moderately procyclical during the postwar era when the input-output structure becomes more sophisticated. Figure 3 also shows that, as rises, the uctuations in real GDP become more persistent. The key to understanding why the model here is capable of generating the desired patterns of real wage movements while at the same time producing signicant output persistence is to observe the response of marginal production cost to the shock. In this case, the marginal cost records not only the nominal wage index and the capital rental rate, but also the intermediate input price. The rigidity in the price of intermediate input due to staggered nominal contracts transmits into the sluggishness in the movements of this third part of the marginal cost and, as the share of intermediate input rises, the marginal cost becomes less procyclical even when the real wage becomes more so. A less variable marginal cost increases the rigidity in rms pricing decisions and opens the way for the model to generate output persistence and to turn the response of the real wage from being countercyclical or acyclical into being weakly procyclical. A natural question is that, as the input-output structure becomes more sophisticated, as is quite plausible in the future, would the real wage tend to become perfectly correlated with real GDP? The answer is negative. For the sake of argument, we extend the value of from its postwar benchmark of 0.7 to an extreme value of 0.9 to capture a possibly more sophisticated input-output structure in the future. We nd that the correlation would not exceed 0.60. There are two factors in the model that prevent the real wage from becoming perfectly correlated with real GDP even as grows arbitrarily close to one. First, nominal wages are sticky. Second, deviations of the nominal wage index from the intermediate input price tend to induce rms
22
These numbers, as well as the numbers displayed in Section V(D) below, are generated by simulating
the (quarterly) baseline model with the money growth processes calibrated to U.S. data. The statistics from the model are computed using BK-ltered articial time series and are averages of those obtained from 200 independent random draws of the shock processes, each with a length of 300 quarters. We discard the rst 100 observations in each time series to avoid dependence on initial conditions.
18
to substitute away from labor and toward materials. The greater is the share of intermediate input, the larger the factor substitution eect is. Thus, even if the input-output structure is to become more sophisticated in the future, our model predicts that real wages may remain moderately procyclical. D. Did Changes in Monetary Policy Shock Process Drive the Results? The monetary policy shock process in the baseline model is calibrated to the postwar U.S. data. Since the policy may have changed from the interwar to the postwar period, one could reasonably argue that changes in the monetary policy shock processes, rather than the increasing complexity of input-output structure, might be responsible for the observed evolution in the cyclical behavior of real wages in the U.S. economy. In other words, did changes in monetary policy shock process drive our results? To answer this question, we begin by calibrating the interwar monetary policy shock process using quarterly U.S. M1 data from 1919:I to 1939:IV [taken from Robert J. Gordon (1986, Appendix B, pp. 803-805)], assuming that the money growth rate follows the same process as in (12), but with potentially dierent parameters. A simple autoregression of the money growth rate yields = 0.75 and = 0.0167 for the interwar period. We then compare the models predicted cross-correlations between real wages and output under the interwar shocks versus the postwar shocks. Figure 5 shows that the results are not sensitive to changes in the shock processes. In particular, for any xed value of in the plausible range for the two sample periods, the correlation coecient does not switch sign as the monetary shock process switches from the interwar one to the postwar one. For example, if is xed at 0.4, the real wage stays countercyclical regardless of which shock process is used; similarly, if is xed at 0.7, the real wage remains procyclical regardless of the shock process. When increases from the interwar benchmark value of 0.4 to the postwar benchmark value of 0.7, the real wage switches from weakly countercyclical in the early years to weakly procyclical in the more recent periods, regardless of the money shock process. This nding does not provide for a support to the notion that changes in monetary policy process have caused the change in the cyclical patterns of real wages over time. By calibrating monetary shock processes for the two periods separately, we can also address a related issue: Can the model generate the observed changes in the business cycle properties of real GDP? In particular, does the model predict more persistence and less volatility in real 19
GDP as the U.S. economy moved from the interwar period to the postwar era, an observation documented in the literature (e.g., J. Bradford Delong and Lawrence H. Summers (1986))? To answer this question, we compare the autocorrelations and standard deviations of output in the two sample periods under the two separate money shock processes. If we take = 0.4 and 0.7 as the respective benchmark value of the intermediate input share in the prewar and the postwar periods, then, under the interwar shock process, the autocorrelation coecient in output is 0.79 and the standard deviation is 0.13; under the postwar shock process, the autocorrelation increases to 0.80 while the standard deviation falls to 0.06. Given that the standard deviation of the innovation to M1 growth rate was larger in the interwar period than that in the postwar period (0.0167 versus 0.008), the falling volatility in real GDP is perhaps not surprising. The more interesting result is that output persistence has slightly increased across the two sample periods, even though the money growth process has become much less persistent (the autocorrelation coecient in the M1 growth process has fallen from 0.75 to 0.68). Our model suggests that a main driving force of the output persistence is the inputoutput connections. The models ability to generate the observed changes in the business cycle properties of real GDP over time lends further credence to the view that the complexity of input-output structure is an important business cycle propagation mechanism. A further question is: What are the models implications on other business cycle properties? This question is important because our model belongs to the class of stochastic dynamic general equilibrium models in the spirit of Finn Kydland and Prescott (1982), and in this strand of literature, an important criterion of evaluating the models performance is to look at a fairly comprehensive set of business cycle facts within a single model. Table 2 reports the business cycle statistics from the model calibrated to quarterly U.S. data for the two sub-sample periods. The model predicts that, in both sub-sample periods, the relative volatility of consumption, measured by its standard deviation relative to that of real GDP, is about 0.26, the relative volatility of investment is about 2.91, and of aggregate employment, it is about 1.68; and that these variables are all highly correlated with output. It is remarkable that, the business cycle properties of our model with a single money supply shock closely resemble those obtained in a standard real business cycle model with a single technology shock [e.g., Cooley and Prescott (1995, Table 1.2, p. 34)]. Further, these business cycle statistics in our model, unlike the
20
cyclical behavior of the real wage, are not sensitive to changes in , nor to changes in the money growth processes.23 E. Quantitative Implications on the Cyclical Behavior of Real Wages We have thus far established the intuitions on the mechanism through which the model can generate the switch of the cyclical behaviors of real wages over time, we now turn to assessing the models ability in capturing the quantitative dierences in the correlations between real wages and output across the interwar and the postwar periods in the U.S. economy. As we have surveyed in Section II, empirical evidence suggests that the correlation of real wages with output has switched signs from the interwar period to the postwar period. This evolving pattern survives for dierent types of data, real wage denitions, detrending methods, and estimation procedures. For this reason, we take the correlation statistics from Basu and Taylor (1999a, Table A2) as a representative of this stylized fact in the large body of literature, and we explicitly confront our models predictions to these statistics in the data. Since Basu and Taylor (1999a) use annual U.S. historical data to compute their correlation statistics, while we have here a quarterly model, we make our models quantitative predictions comparable to the data by rst simulating the quarterly model to obtain articial time series, and then converting the quarterly series into annual series using the same temporal aggregation methods in constructing the actual annual data.24 In addition, Basu and Taylor (1999a) apply
23
The relative volatility of employment seems to be slightly higher than one would expect. This is so because
we have here a demand-shock driven model where nominal wages and prices are sticky. One way to lower the employment volatility (so as to bring the models predictions somewhat closer to the data) in this class of models might be to introduce productivity shocks that are uncorrelated with the monetary shocks: while an expansionary monetary shock tends to increase employment, an improved productivity tends to reduce it since output is demand determined as a result of sticky prices [e.g., Gali (1999)]. We do not pursue this line here because, as we have argued in the introduction and surveyed in Section II, a story that relies on dierent mixtures of shocks does not seem to be a plausible explanation of the evolution of the cyclical behavior of real wages. 24 In practice, the data on GDP and its components are collected by the BEA, and are treated as ow variables, so that the annual series are simple sums of the corresponding quarterly series. The data on wages (or compensations) are collected by the BLS, and are treated also as a ow variable (since wages are measured on a per time period basis), with the annual series obtained by summing up the quarterly series. The data on consumer price indices are collected by the BLS as well, but unlike the wage data, the price indices are treated as a stock variable so that the annual series are averages (rather than sums) of the quarterly series.
21
the BK lter to their annual data to isolate the business cycle components before they compute the correlation statistics. We do the same to the annual time series generated from the model. To examine the robustness of the results, we also consider the models predicted correlations when the HP lter is applied to the articial time series. Table 3 displays the correlations between real wages and aggregate output in the data and those generated from the model. The model does quite well in capturing the switch of the cyclical behaviors of real wages across the two sample periods, regardless of the ltering methods. In the baseline case with the BK-ltered time series, the models predicted correlations match the data closely for both sample periods. In particular, during the interwar period, the correlation is 0.444 in the data and 0.492 in the model; during the postwar period, the correlation in the data grows into a range between 0.381 and 0.503, and the model predicts a value of 0.470. Further, we nd that these quantitative results are not sensitive to the particular detrending method used here: applying the HP lter instead of the BK lter produces essentially the same results. VI. Conclusion We have developed a dynamic stochastic general equilibrium theory that links two prominent empirical regularities in the U.S. economy. The model with staggered price- and wagesetting and a roundabout input-output structure provides a unied framework that oers a potential explanation for the mildly countercyclical or acyclical behaviors of real wages seen at early times when production involved simple input-output relations, and the mildly procyclical real wages observed in more recent years when the input-output connections have become more sophisticated. To help illustrate this point, we have kept our model as simple as possible. Yet, our results suggest some potential extensions of the model. For example, existing evidence suggests that, in the postwar U.S. economy, real wages are more procyclical in the manufacturing sector than at the economy-wide level, and within the manufacturing sector, they are more procyclical in the durable goods industries than in the non-durable goods industries [e.g., Christiano, et al. (1997)]. Casual observations suggest that the share of intermediate inputs is larger in the manufacturing sector than in other sectors (such as the raw material sector and the service sector), and within the manufacturing sector, it is larger in the durable goods industries (such as the electronic equipment industries) than in the non-durable goods industries (such as the 22
petroleum and coal industries). The results presented in this paper lead us to conjecture that the diering shares of intermediate inputs across sectors or industries are likely to be important in accounting for the observed dierences in the behaviors of sectoral or industrial real wages. A formal analysis of this sort calls for an extension of our model to a multi-sector setup with the shares of intermediate inputs in dierent sectors calibrated to those in the actual economy, and with some kind of impediments to the mobility of labor across sectors. The model has potentially other testable implications. For example, our results suggest that real wages can be more procyclical in developed countries than in developing countries, since the input-output structures tend to be more sophisticated in the former than in the latter. Needless to say, a more careful analysis should take international connections and the transmissions of shocks across countries into account. This calls for an extension of our model to a global economy setup with countries at dierent stages of development and with real and nominal linkages across countries incorporated. Existing theoretical studies suggest that the cross-country input-output linkages in the actual economies can be an important international monetary transmission mechanism [e.g., Paul Bergin and Robert C. Feenstra (2001) and Huang and Liu (2003a, b)]. There is also much empirical evidence regarding the impacts of dierent exchange rate regimes on the transmissions of monetary shocks and the behaviors of real and nominal economic variables [e.g., Basu and Taylor (1999b)]. The results presented here and the existing theoretical and empirical ndings alluded to indicate that future research along this avenue should be both necessary and fruitful. Appendix In this appendix, we present an alternative model structure that does not require the implicit nancial arrangements assumed in the baseline model for aggregation purposes. We show that this alternative model generates identical equilibrium dynamics as in the baseline model. The good market structure remains the same as in the baseline model, but the labor market structure diers. Here, instead of assuming a continuum of households with dierentiated labor skills, we assume that there is a representative household with a large number of family members, each endowed with a raw labor skill. The representative household derives utility from consumption of a composite good and holdings of real money balances, and it also cares 23
about each members disutility of working. The lifetime discounted utility of the household is given by (18)
t=0 st
t (st ) ln C (st )
1 0
L(i, st )1+ di , 1+
where C (st ) is a CES composite of the households consumption and real money balances (as in the text), and L(i, st ) is the quantity of type i raw skills supplied by member i of the household at st .25 The budget constraint facing the household in event history st is given by P (st )Y (st ) +
st+1
D(st+1 |st )B(st+1 ) + M (st )
(19)
1 0
(i, st )L(i, st )di + Rk (st )K(st1 ) + (st ) + B(st ) + M (st1 ) + T (st ),
where (i, st ) is the price of raw skills of type i, and other notations are the same as in the baseline model (without the individual index). The composite good Y (st ) can be either consumed or invested. Thus (20) Y (st ) = C(st ) + K(st ) (1 )K(st1 ) + (K(st ) K(st1 ))2 . K(st1 )
Note that, since we have a representative household, we do not need to impose the implicit nancial arrangement as in the baseline model for the purpose of risk-sharing (as a consequence, equilibrium consumption and investment are always identical for each household). The optimal consumption-leisure choice implies that the marginal rate of substitution between member is leisure and income equals the nominal price of is raw skill, that is, M RS(i, st ) = (i, st ) for all i and all st . The members of the household cannot directly supply their raw...