Strategic complementarity slows macroeconomic adjustment to temporary shocks.
Oh, Seonghwan ; Waldman, Michael
I. INTRODUCTION
Starting with the work Of Diamond [1982], Hart [1982], and Bryant
[1983], a number of authors have employed models which use potential
coordination failure to show that many features of the Keynesian
framework can be captured in models consistent with the microfoundations
approach.(1) For example, in the context of a search model Diamond
demonstrates the existence of equilibria with "too low" a
level of aggregative activity, Hart captures this feature and the
simultaneous existence of multipliers in a model of monopolistic
competition, while technological interactions are the crucial element of
Bryant's analysis. One reason to refer to these seemingly diverse
set of papers as a single literature is that all the models are in fact
driven by the presence of the same factor: strategic complementarity. A
macroeconomic model which exhibits strategic complementarity is simply
one where, the larger is aggregate production, the larger is the
incentive for any particular agent to produce. Cooper and John [1988]
first demonstrated that the presence of strategic complementarity is a
characteristic of all of the models mentioned above, and persuasively
argue that this is the critical feature which lies behind the finding of
Keynesian-type results.
In this paper we argue that strategic complementarity is also
important in understanding the dynamic response of economies to
temporary shocks. In particular, we find that strategic complementarity
is potentially an important factor in understanding why an economy may
return only slowly to steady-state behavior after a temporary shock.
That is, given the presence of any of a variety of factors which would
cause the economy not to instantaneously return to full employment after
a temporary shock (e.g., adjustment costs associated with changing the
capital stock), the speed with which the economy returns to steady-state
behavior is negatively related to the degree of strategic
complementarity in the environment.
Related analyses are those of Haltiwanger and Waldman [1989], Bomfim
and Diebold [1992], and Baxter and King [1990]. The first two papers
consider models wherein some agents are characterized by adaptive or
regressive expectations while others am characterized by rational
expectations. Among other findings, these analyses demonstrate that the
speed with which the economy returns to steady-state behavior after a
temporary shock is negatively related to the degree of strategic
complementarity in the economy.(2) We argue that the relationship
between strategic complementarity and the dynamic response to temporary
shocks is more general than is suggested by these papers. In their
analyses temporary shocks have long-term effects because some of the
agents make systematic mistakes when forming expectations. Here it is
argued that, given any of a variety of factors which would cause
temporary shocks to have long-term effects, there is a negative
relationship between adjustment speed and the degree of strategic
complementarity.
Baxter and King consider a world where, because of productive
externalities, the economy exhibits increasing returns at the
economy-wide level. Using simulation techniques they show, first, that
the presence of increasing returns serves to increase the output
volatility exhibited by the economy in response to shocks and, second,
that after a one-time shock the return to steady-state behavior is
slower in a world characterized by increasing returns. Baxter and King
do not discuss their results in terms of strategic complementarity.
However, it is easy to show that one way of introducing strategic
complementarity is to assume that the economy exhibits increasing
returns at the economy-wide level. Our paper suggests that what is
central in Baxter and King's study is not the introduction of
increasing returns per se, but rather that the introduction of
increasing returns is one way of introducing strategic complementarity.
That is, Baxter and King's findings can be thought of as a
manifestation of the central point of the current paper.
The outline for the paper is as follows. Section II presents a simple
stylized model that illustrates the relationship between strategic
complementarity and the speed of return to steady-state behavior at the
most basic and abstract level. Section III analyzes a richer model
characterized by strategic complementarity and capital-stock adjustment
costs. Section IV discusses models in which temporary shocks have
long-term effects for reasons other than capital-stock adjustment costs.
Section V presents some concluding remarks.
II. A STYLIZED MODEL
In this section we develop a simple stylized model which illustrates
in a clear fashion the relationship between strategic complementarity
and speed of return to steady-state behavior.3 Let firm i' s
frictionless reaction function be given by [y.sub.i,t] = [ay.sub.t] +
[e.sub.t], 0 < a < 1. The variable [y*.subi,t] is firm i' s
output in period t in the absence of adjustment costs, [y.sub.t] is the
average output per firm in period t, a is the parameter that measures
strategic complementarity, and et is the value of an exogenous parameter
in period t. Equation (1) is derived by imposing the partial-adjustment
equation [y.sub.i,t] = [by.sub.i,t] + (1-b)[y.sub.i,t], 0 < b < 1,
onto this frictionless reaction function, where b is the parameter that
measures the slowness of the individual firm's adjustment path.
[MATHEMATICAL EXPRESSION OMITTED]
We can solve for the symmetric equilibrium by setting [y.sub.i,t] =
[y.sub.t]. This yields equation (2) as the condition which must be
satisfied in short-run equilibrium.
[MATHEMATICAL EXPRESSION OMITTED]
Further, substituting et = e for all t and [y.sub.t] = [y.sub.t-1]
yields equation (3) as the condition which characterizes long-run
equilibrium or steady-state behavior.
(3) [y.sub.t]: [1/(1 - a)]e.
A comparison of equations (1) and (2) illustrates the central
argument of the paper. Equation (1) states that at the individual- firm
level the slowness of the adjustment path--captured by the coefficient
b--is independent of the degree of strategic complementarity. In
contrast, equation (2) tells us that at the macro level the slowness of
the adjustment path--captured by the term b/[1-(1-b)a]--depends not only
on b but on the value of the parameter which measures the degree of
strategic complementarity. In particular, if there is a one-time
temporary shock to the value of the exogenous parameter e, then the
greater is a the larger is b/[1- (1- b)a] and thus the slower is the
return to steady-state behavior.
The intuition behind this result is as follows. Suppose there is a
one-time temporary shock which causes average output per firm to fall
below the steady-state average output level. During the adjustment
period all firms will have low output, and the representative firm will
want to keep its output low for two reasons. First, because of its own
adjustment costs it does not want to go immediately to the steady-state
output level. Second, given the presence of strategic complementarity,
the representative firm will want to keep its output below the
steady-state level because all other firms' outputs are below the
steady-state level. It is this second factor which at the macro level
causes the speed of return to steady-state behavior to be negatively
related to the degree of strategic complementarity.
To further illustrate the argument consider the following numerical
example. Let b = 1/2 and suppose that through period T-1 the economy is
in the steady-state equilibrium where et = 0 for all t. Further, in
period T assume e rises such that [y.sub.T] = 1, and then (e.sub.t) = 0
for all t > T. (4) Figure 1 depicts the adjustment path for [y.sub.t]
following the one-time shock to e for various values of a. There are two
points to note about the diagram. First, the return to steady-state
behavior is slower when strategic complementarity is present, i.e., when
a > 0. Second, as discussed above, the higher is the degree of
strategic complementarity the slower is the return to steady-state
behavior.
III. A MODEL WITH CAPITAL-STOCK
ADJUSTMENT COSTS
In this section we demonstrate that the results discussed above hold
in a more fully specified macroeconomic model.
The Model
We construct a macroeconomic model similar to one analyzed in
Haltiwanger and Waldman [1989]. The main differences are, first, that
all agents here are assumed to have rational expectations and, second,
agents (i.e., firms) now face adjustment costs for changing their
capital stock.
The model is also related to the analyses of Bryant [1987], Kiyotaki
[1988], and Well [1989]. Their papers consider environments
characterized by investment opportunities and strategic complementarity
and demonstrate the possibility for multiple equilibria which vary in
terms of the rates of investment and growth in the economy. Our model
considers the same type of economy, but rather than examining the
possibility of multiple equilibria, we focus on the adjustment path
which the economy follows in response to a temporary shock.
Consider a continuum of risk-neutral agents who must decide each
period on an output level. Let [Y.sub.i,t] denote agent i' s
production level in period t. The cost to agent i of producing
[Y.sub.i,t] is denoted [c.sub.i,t], where [c.sub.i,t] =
(y.sub.i,t])[sup.2]/(1 + k.sub.i,t]). The term [k.sub.i,t] is the size
of agent i' s capital stock in period t. The specification
therefore states that the larger is the capital stock in period t, the
smaller is the cost of producing any fixed output level in that period.
The manner in which [k.sub.i,t] is determined is described below.
Let [Y.sub.t] be period t' s aggregate production. The gross
return to an agent from producing an amount [y.sub.i,t] is given by
[Gamma.([Y.sub.t]) [y.sub.i,t], where [Gamma'] > 0. The
assumption [Gamma'] > 0 means that the economy exhibits
strategic complementarity, i.e., an increase in aggregate production
raises the incentive for each individual firm to produce.(5)
Given the assumption [Gamma'] > 0, we can interpret this
model in terms of a number of existing macroeconomic models of
coordination failure. For example, consider Diamond [1982]. In that
model the key restriction on behavior is that each individual is better
off trading rather than consuming what he produces. Under this
interpretation, [Gamma'] > 0 indicates the presence of positive
trading externalities. That is, the larger is aggregate production, the
higher is the probability that any particular trader will successfully
complete a trade.
One can also interpret [Gamma'] > 0 as arising from demand
linkages between imperfectly competitive producers in a multisector
economy as in Hart [1982]. Under this interpretation, [Gamma(Y.sub.t])
denotes the marginal revenue from production, and [Gamma'] > 0
indicates that demand linkages cause the marginal revenue function
facing a producer in a particular sector to shift out as the outputs of
other sectors increase.
We now discuss the determination of [k.sub.i,t]. Agent i must split
his net return in each period between consumption and investment. For
simplicity we assume that it takes one period to construct capital. To
be specific, [k.sub.i, t+1] is given by where (1-6) is a depreciation
term and thus falls in the interval (0,1), and [w.sub.i,t] is agent
i' s investment expenditure in period t.(6) It is assumed that a
firm faces adjustment costs for changing its capital stock, i.e., m(0) =
0, m'(0)--[infinite], and m'(w) > 0, m"(w) (0 for all
w > 0. The term [u.sub.t +1] is a parameter shared by all the agents,
which captures the productivity of investing in capital. It is assumed
that each agent chooses his expenditures on capital to maximize the
discounted expected value of his consumption stream, where each agent
discounts the future by a factor [Beta].
The model we have described above may display multiple steady-state
equilibria because strategic complementarity is present. Since we want
to abstract away from this possibility, we impose the following
conditions:
[MATHEMATICAL EXPRESSION OMITTED]
where Y(k) is defined by the equation Y(k)/r[Y(k)] = (1 + k)/2 for
all k [greater than or equal to] 0 and n = [m.sup.-1). Equation (5)
guarantees that for a fixed value of k, the resulting value for Y is
unique. Equation (6) ensures that the return to investing in capital is
sufficiently concave to guarantee a unique and stable steady-state
equilibrium.
Analysis
As in section II, the focus of our analysis is on how the economy
responds to temporary shocks, in particular on how the path of
adjustment following a shock is affected by the degree of strategic
complementarity in the economy. We will consider shocks to the
productivity of capital investment. Below (Y.sup.S (micro) denotes the
steady-state value for Y when [u.sub.t], the productivity of capital,
equals [micro], its steadystate value, in every period.
We begin by investigating how our model economy responds to an
anticipated temporary shock. In particular, proposition 1 states the
response of the economy to a shock of the following form. Up to period
T-2 the economy is in a steady-state where p = [micro]. In period T - 1
all the agents learn that Pt = P for all periods except T, while
[micro.sub.T]= [micro]. (All proofs are contained in the appendix.)
PROPOSITION 1. Given an anticipated temporary shock, then (i) and
(ii) hold if [micro] > (<) [micro]
[MATHEMATICAL EXPRESSION OMITTED]
That is, following an anticipated temporary shock the economy
gradually returns to the original steady-state production level. What
happens is that the shock causes capital-stock holdings to change both
because agents alter their investment plans, and because of a direct
change in the productivity of investing in capital. In turn, the changed
values for capital-stock holdings result in the economy only slowly
returning to the original steadystate production level.
Proposition 1 is not very surprising. Given the specification of the
function m(.), i.e., that each agent faces adjustment costs for changing
his capital stock, it would be surprising if the model did not exhibit
long-term effects of temporary shocks.(7) We now turn our attention to a
more interesting question, specifically what is the relationship between
the speed with which the economy returns to steady-state behavior and
the degree of strategic complementarity. In order to investigate this
issue we characterize a transformation of r(.) that increases the degree
of strategic complementarity. Suppose [^Gamma(Y*)= r(Y*). Then [^r(-)]
represents an increase in the degree of strategic complementarity if
[^r(Y)] > r'(Y) for all Y. In other words, an increase in the
degree of strategic complementarity involves an increase in the slope of
r(.) around some fixed point.
PROPOSITION 2. Suppose the economy experiences the type of
anticipated temporary shock considered in proposition 1. A
transformation of r(.) which increases the degree of strategic
complementarity but leaves [Y.sup.S(micro)] unchanged will cause
[Y.sub.t]-[Y.sup.S(micro)] to increase for every t > T.
Proposition 2 considers the following hypothetical case. Suppose
there is an increase in the degree of strategic complementarity which
leaves steady-state behavior unchanged. The speed with which the economy
returns to steady-state behavior is negatively related to the degree of
strategic complementarity. The logic behind this result is similar to
that given in the previous section. Suppose there is a shock which
causes capital stock holdings in period T to fall below their steady
state values. Should an agent invest so as to quickly return capital
stocks to the steady-state level? Since during the adjustment period
aggregate production is below its steady-state value, the incentive to
invest is negatively related to the degree of strategic complementarity.
In turn, because the incentive for investing is reduced by an increase
in strategic complementarity, we find that an increase in strategic
complementarity serves to decrease the speed of adjustment following the
shock.
One question of interest concerns the robustness of our findings to
different types of shocks. An increase in strategic complementarity
increases the initial impact of an anticipated shock, while decreasing
the speed with which the economy returns to steady-state behavior. We
would like to know whether this relationship between speed of adjustment
and strategic complementarity holds for shocks whose initial impact is
not increased by an increase in strategic complementarity. To
investigate this issue we now consider an unanticipated shock. We assume
that the economy is in a steady state where [micro] = [(-)/micro] up to
period T - 2.
In period T - 1 the agents choose expenditures on capital assuming
that the economy will remain in the steady state. In fact, however,
[micro.sub.T] = [micro], and the agents only find this out in period T.
Finally, for every period subsequent to T it is the case that Pt = g,
and agents make their investment decisions in those periods knowing this
is the case.
It is easy to demonstrate that in response to this type of
unanticipated shock the economy works in a fashion similar to the
anticipated case considered in proposition 1. That is, an unanticipated
shock causes a change in capital-stock holdings and because of
adjustment costs there is only a slow return to the steady state. The
reason the unanticipated shock is of interest is that in this case an
increase in the degree of strategic complementarity has no effect on how
current activity is affected by a temporary shock (see proposition 3
below). Thus, we can investigate the significance of strategic
complementarity in an environment where the initial impact of the shock
does not depend on the degree of strategic complementarity.
PROPOSITION 3. Suppose the economy experiences the type of
unanticipated temporary shock described above. A transformation of r(.)
which increases the degree of strategic complementarity but leaves
[Y.sup.s](micro) unchanged will also leave [Y.sub.T]- [y.sup.s] (micro)
unchanged, but will cause [Y.sub.T] - [Y.sup.S.(micro)] I to increase
for every t>T.
Proposition 3 indicates that what is driving our results is not
simply that an increase in strategic complementarity increases the
initial impact of a temporary shock. Rather, even in a world where the
initial impact is unaffected by the degree of strategic complementarity,
it is still the case that an increase in strategic complementarity
decreases the speed with which the economy returns to steady state
behavior. The intuition is as given above. An increase in strategic
complementarity decreases (increases) the incentive to invest after the
economy is hit by a negative (positive) shock. Hence, an increase in
strategic complementarity serves to inhibit the economy's return to
steady-state behavior.
As a final point, we would like to mention that it would be easy to
extend our results to the type of persistent shocks which are currently
popular in the real business cycle literature. For example, suppose that
[micro.sub.T] = [micro] and [micro.sub.T+j]= [Lambda.sup.j]([micro] - [-
micro) + - micro] for all j > 0, where 0 < [Lambda] < 1. It
would be easy to show that for this type of shock one could derive
propositions similar to propositions 2 and 3.
IV. OTHER FACTORS WHICH CAUSE TEMPORARY SHOCKS TO HAVE LONG-TERM
EFFECTS
In the previous section we considered a model where each agent faces
adjustment costs for changing his capital stock, and demonstrated that
the presence of strategic complementarity may be an important factor in
explaining the speed of recovery after a temporary shock. In this
section we argue that this conclusion is quite general. That is, given
the presence of any one of a variety of factors which would cause the
economy not to instantaneously return to full employment after a
temporary shock, the presence of strategic complementarity will be an
important determinant of the speed of the economy's return to
steadystate behavior. In what follows, so as to avoid redundancy with
propositions derived in the previous section, the argument will proceed
on an informal rather than on a formal basis.
Adaptive Expectations
Another reason why temporary shocks may have long-term effects is
because some or all of the agents are characterized by adaptive
expectations. This factor was analyzed in Haltiwanger and Waldman
[1989], and a related analysis appears in Bomfim and Diebold [1992]. In
particular, Haltiwanger and Waldman considered a variant of the model
presented above wherein a subset of agents form their expectations for
[Gamma(Y.sub.t)] in an adaptive fashion, and capital is not part of the
production process. They also found that an increase in the degree of
strategic complementarity serves to decrease the speed of return to
steady-state behavior after a temporary shock.
One can understand their result by considering an economy populated solely by agents with adaptive expectations. Suppose that in such an
economy there is a temporary shock which causes [Gamma(Y.sub.t)] to fall
below its steady-state value by some fixed amount. This will lower the
expectation agents have for [Gamma(Y.sub.T+1)], which in turn will
reduce aggregate output in T+1. However, for any fixed decrease in
output in T+1, the realized value for [Gamma(Y.sub.T+1)] will be smaller
the higher is the degree of strategic complementarity. What this implies
is that, since the realized value for affects the expectation agents
have for [Gamma(Y.sub.T+2)] aggregate output in period T+2 will be
smaller the higher is the degree of strategic complementarity. In turn,
continuously repeating this argument one finds that for every t > T +
2, the deviation from steady-state output will be higher the higher is
the degree of strategic complementarity.
Sticky Prices
Another factor frequently used to generate long-term effects from
temporary shocks is the existence of sticky prices. This notion has been
formalized in the literature in a number of different ways. For example,
the idea of prices being set in a staggered fashion goes back to the
work of Fischer [1977] and Taylor [1980], menu costs have been explored
in the work of Akerlof and Yellen [1985] and Mankiw [1985], while Ball
and Cecchetti [1988] and Ball and Romer [1989] focus on whether sticky
prices arise in models where the timing of price changes is assumed to
be endogenous. We argue here that, if temporary shocks have long-term
effects because of sticky prices of one type or another, the speed with
which the economy returns to steady-state behavior will be negatively
related to the degree of strategic complementarity.
We put forth our argument in the context of a monopolistic
competition model where price setting is staggered, i.e., half the firms
set their prices every even period while the other half set their prices
every odd period. We also assume that the economy exhibits strategic
complementarity in prices--that is, a firm's optimal price is an
increasing function of the aggregate price level? Starting from a steady
state, consider how this economy responds to a one-time unanticipated
increase in the money supply which occurs in, say, period T. Group A
will refer to the set of firms which set their prices in periods T, T+2,
T+4, etc., while group B will refer to the set of firms which set their
prices in periods T+I, T+3, etc. In period T+1 group B firms will want
to increase their prices, but not all the way to the new steady-state
levels. The reason is that in period T+1 group A firms will remain at
the old steadystate prices, and given strategic complementarity, this
provides an incentive for the group B firms to only partially adjust.
Further, the higher is the degree of strategic complementarity the
higher will be the incentive for group B firms to only partially adjust,
and thus the lower will be the prices set by group B firms in period
T+1. In turn, repeating this argument for periods T+2, T+3, etc., one
has that for every t > T + 1, the difference between the actual price
level and the eventual steady- state price level will be an increasing
function of the degree of strategic complementarity in the environment.
In other words, just as was true under the capital-stock adjustment-cost
assumption and the adaptive-expectations assumption, the speed with
which the economy adjusts to the new steady state is negatively related
to the degree of strategic complementarity.
Finally, although the argument above is put forth in the context of a
specific model of sticky prices, our conjecture is that the result is
quite general. That is, given almost any reasonable specification under
which sticky prices cause temporary shocks to have long-term effects, we
conjecture that the speed with which the economy adjusts to the new
steady state will be negatively related to the degree of strategic
complementarity.
Other Types of Adjustment Costs
As a final point, we would like to make clear that although the
formal model of section III focuses on adjustment costs associated with
a firm changing its capital stock, the argument applies much more
generally. In particular, our feeling is that almost any adjustment-cost
model consistent with temporary shocks having longterm effects will be
such that the speed with which the economy returns to steady-state
behavior after a temporary shock will be negatively related to the
degree of strategic complementarity in the environment.
Consider for example a model of monopolistic competition and
inventories, where each firm faces adjustment costs for changing its
level of inventory holdings. Suppose further that in period T there is
an unanticipated temporary shock to the economy which causes aggregate
inventory holdings to rise. Blinder and Fischer [1981] consider just
such a model and demonstrate that the response of the economy to this
temporary shock will be an immediate fall in aggregate output, and then
a gradual return to the original steady- state level. We can now
consider the role that strategic complementarity would play in such an
environment. Consider period T+1. Since during the adjustment phase
aggregate production is below its steady-state value, in period T+1 the
incentive to produce will be smaller the larger is the degree of
strategic complementarity. In addition, since the incentive to run down
excess inventories is positively related to the incentive to produce,
there will also be a negative relationship between the incentive to run
down inventories and the degree of strategic complementarity. The result
is that aggregate output in period T+1 will be negatively related to the
degree of strategic complementarity, while aggregate inventory holdings
at the end of period T+I will be positively related to the degree of
strategic complementarity. In turn, repeating this argument for periods
T+2, T+3, etc., yields that, just as was true for the capital-stock
adjustment-cost model of section III, for every t > T + 1 the
deviation from steadystate behavior will be positively related to the
degree of strategic complementarity in the environment.
V. CONCLUSION
The presence of strategic complementarity in macroeconomic models has
been used to explain a host of important phenomena, e.g., multipliers,
multiple equilibria, and the possibility of underemployment equilibria.
In this paper we argue that the presence of strategic complementarity in
the macro setting is also important for understanding why an economy may
exhibit a slow return to steady-state behavior after a temporary shock.
In particular, we argue that given the presence of any one of a variety
of factors which would cause the economy not to instantaneously return
to full employment after a temporary shock, the speed of adjustment is
negatively related to the degree of strategic complementarity.
One way in which the analysis of this paper might fruitfully be
extended is to consider the concept of the automatic stabilizer. In an
earlier literature on economic fluctuations the concept of the automatic
stabilizer was a central element for explaining why the post-World War
II economy seems to be less prone to large fluctuations than the
pre-World War II economy. The logic was that there were changes in the
system of governing, e.g., changes in the tax system, which reduced
economic instability in response to shocks. Our claim is that the
concept of the automatic stabilizer can be at least partially understood
in terms of strategic complementarity. Specifically, our analysis
suggests that any change which serves to reduce the degree of strategic
complementarity should be a type of automatic stabilizer. This follows
from our finding that adjustment speed after a temporary shock is
negatively related to the degree of strategic complementarity. In other
words, exactly consistent with the definition of an automatic
stabilizer, any change which reduces the degree of strategic
complementarity should reduce the instability the economy exhibits in
response to shocks. In future work we hope to more fully investigate
this idea. In particular, our plan is to formally investigate the links
between strategic complementarity and those aspects of the post-World
War II economy that earlier authors have identified as automatic
stabilizers.
[TABULAR DATA OMITTED]
APPENDIX
PROOF OF PROPOSITION 1. To prove proposition 1 we must first
demonstrate that the economy is characterized by a unique and stable
steady-state equilibrium. Since we assume a continuum of agents in the
unit interval, total output as a function of the period t capital stock,
[Y(k.sub.t)], is defined by the expression
[Y(k.sub.t)]/[Gamma[Y(k.sub.t)]] = (1 + [k.sub.t])/2. This follows from
each agent producing to the point where the marginal cost of production
equals the marginal revenue of production. Given a fixed value for
[k.sub.t], we now have that equation (5) is a sufficient condition for a
unique [Y.sub.t].
The representative agent solves the following maximization problem.
[MATHEMATICAL EXPRESSION OMITTED]
Let n = [m.sup.-1]. Since m'> 0 and m"< 0, we have
that n' > 0 and n" > 0. (Al) can be rewritten as
[MATHEMATICAL EXPRESSION OMITTED]
We can easily demonstrate that (A2) is a well-defined dynamic
optimization problem, and thus sufficient conditions for an interior
solution are the Euler equation and the transversality condition.
[MATHEMATICAL EXPRESSION OMITTED]
Note that for deriving the equations above the representative agent
takes the sequence of [Y.sub.'t s] as given, rather than as a
function of his own actions. Given equation (6), (A3) and (A4) yield
that there exists a unique steady state which is defined by (A5), where
k* denotes the steadystate value of the capital stock.
[MATHEMATICAL EXPRESSION OMITTED]
Given n'(0) = 0 and [gamma](0) > 0 (see footnote 5), (AS)
yields that k* > 0.
To consider stability we first take a linear approximation of the
Euler equation around k*
[MATHEMATICAL EXPRESSION OMITTED]
Rewriting (A6) we obtain
[MATHEMATICAL EXPRESSION OMITTED]
The characteristic polynomial for A is
[MATHEMATICAL EXPRESSION & TEXT OMITTED]
It is clear that equation (6) is sufficient for one of the roots to
lie between zero and one. The other root exceeds one. Thus by Theorem 6.9 in Stokey and Lucas [1989] the above steady state is stable. Also,
the fact that 0 < Lambda.sub.1! < 1 implies that adjustment paths
are monotonic. Finally, [Lambda.sub.1] is given by equation (A9).
PROOF OF PROPOSITION 2. (A3) and (A9) yield
[MATHEMATICAL EXPRESSION OMITTED]
PROOF OF PROPOSITION 3. This proof follows along the same lines as
that of proposition 2 except that agents now choose [w.sub.T-1] given a
belief that [micro.sub.T] = [micro]
REFERENCES
Akerlof, George, and Janet Yellen. "The Macroeconomic
Consequences of Near-Rational Rule-of-Thumb Behavior." Quarterly
Journal of Economics, Supplement 1985, 823-38.
Ball, Laurence, and Stephen Cecchetti. "Imperfect Information
and Staggered Price Setting." American Economic Review, December
1988, 999-1018.
Ball Laurence, and David Romer. "The Equilibrium and Optimal
Timing of Price Changes." Review of Economic Studies, April 1989,
179-98.
Baxter, Marianne, and Robert King. "Productive Externalities and
Cyclical Volatility." University of Rochester Working Paper No.
245, September 1990.
Blinder, Alan, and Stanley Fischer. "Inventories, Rational
Expectations, and the Business Cycle." Journal of Monetary
Economics, November 1981, 277-304.
Bomfim, Antulio. "Business Cycle Dynamics, Forecast
Heterogeneity, and Strategic Complementarities: When Do Inefficient
Prediction Rules Start to Matter?" Working paper, Board of
Governors of the Federal Reserve, March 1992.
Bomfim, Antulio, and Frank Diebold. "Near-Rationality and
Strategic Complementarity in a Macroeconomic Model: Policy Effects,
Persistence and Multipliers." Working paper, Board of Governors of
the Federal Reserve, July 1992.
Bryant, John. "A Simple Rational Expectations Keynes-Type
Model." Quarterly Journal of Economics, August 1983, 525-29.
"The Paradox of Thrift, Liquidity Preference and Animal
Spirits." Econometrics, September 1987, 1231-35.
Cooper, Russell, and John Haltiwanger. "Inventories and the
Propagation of Sectoral Shocks." American Economic Review, March
1990, 170-90.
Cooper, Russell, and Andrew John. "Coordinating Coordination
Failures in Keynesian Models." Quarterly Journal of Economics,
August 1988, 441--63.
Diamond, Peter. "Aggregate Demand Management in Search
Equilibrium." Journal of Political Economy, October 1982, 881-94.
Durlauf, Steven, "Multiple Equilibria and Persistence in
Aggregate Fluctuations." American Economic Review, May 1991, 70-74.
Fischer, Stanley. "Long Term Contracts, Rational Expectations,
and the Optimal Money Supply Rule." Journal of Political Economy,
February 1977, 163-90.
Haltiwanger, John, and Michael Waldman. "Rational Expectations
and the Limits of Rationality: An Analysis of Heterogeneity."
American Economic Review, June 1985, 326--40.
"Limited Rationality and Strategic Complements: The Implications
for Macroeconomics." Quarterly Journal of Economics, August 1989,
46383.
Hart, Olivet "A Model of Imperfect Competition with Keynesian
Features." Quarterly Journal of Economics, February 1982, 109--38.
Kiyotaki, Nobuhiro. "Multiple Expectational Equilibria Under
Monopolistic Competition." Quarterly Journal of Economics, November
1988, 695-713.
Leijonhufvud, Axel. Information and Coordination: Essays in
Macroeconomic Theory. New York: Oxford University Press, 1981.
Lucas, Robert. "Understanding Business Cycles," in
Stabilization of the Domestic and International Economy, edited by K.
Brunner and A. Meltzer. Amsterdam: North-Holland, 1977, 7-29.
Mankiw, N. Gregory. "Small Menu Costs and Large Business
Cycles." Quarterly Journal of Economics, May 1985, 529-37
Oh, Seonghwan, and Michael Waldman. "The Macroeconomic Effects
of False Announcements."
Quarterly Journal of Economics, November 1990, 1017-34.
Stokey, Nancy, and Robert Lucas. Recursive Methods in Economics.
Cambridge: Harvard University Press, 1989.
Taylor, John. "Aggregate Dynamics and Staggered Contracts."
Journal of Political Economy, February 1980, 1-23.
Weil, Philippe. "Increasing Returns and Animal Spirits."
American Economic Review, September 1989, 889-94.
* Professor, Department of Economics, Seoul National University, and
Professor, Johnson Graduate School of Management, Cornell University. We
would like to thank Antulio Bomfim, the participants at workshops at
Brown University, Georgetown University, and the Federal Reserve Bank of
St. Louis, as well as two anonymous referees for helpful comments, and
the UCLA Academic Senate for financial support.
1. Later papers include Bryant [1987], Cooper and John [1988],
Kiyotaki [1988], Haltiwanger and Waldman [1989], Weil [1989], Cooper and
Haltiwanger [1990], Oh and Waldman [1990], Durlauf [1991], Bomfim [1992]
and Bomfim and Diebold [1992]. See also Leijonhufvud [1981] for a
non-technical analysis which captures many of the same ideas.
2. In terms of this result, the difference between the two papers is
that Haltiwanger and Waldman consider a microfoundations-type setting,
while Bomfim and Diebold look at a more aggregative economic model. See
also Haltiwanger and Waldman [1985] and Bomfim [1992].
3. We would like to thank one of the referees for suggesting the
analysis of this section.
4. The value of [e.sub.T] which results in yr = 1 depends on the
value of a. Note, if we employed the same value of et for all values of
a considered, then the size of the initial impact of the shock would be
positively related to a. Hence, in this case we would have a second
reason for why the speed of return to steady- state behavior is
negatively related to the degree of strategic complementarity. See
proposition 2 of the following section for a related result.
5. To rule out the possibility of a degenerate equilibrium where the
capital stock equals zero we impose the condition [Gamma(0)] > 0. One
can interpret r(0) as being the gross return from a unit of output when
an individual is unable to trade. Hence, r(0) ) 0 simply states there is
a positive return derived from consuming one's own production.
6. Introducing a time-to-build a assumption would serve to complicate the analysis without changing the qualitative nature of the results.
7. See Lucas [1977] for an earlier discussion concerning capital-
stock adjustment costs and the longterm effects of temporary shocks.
8. Ball and Romer [1989] show that if the timing of pricing decisions
were made endogenous in this type of model, then price setting would not
be staggered. However, Ball and Cecchetti [1988] demonstrate that
staggered price setting would arise if imperfect information were added
to the model.