the inflation tax in a real business cycle model money is incorporated into a real business cycle model using a cash in advance constraint the model economy is used to analyze whether the business cycle is different in high inflation and low inflation economies and to analyze the impact of variability in the growth rate of money in addition the welfare cost of the inflation tax is measured and the steady state properties of high and low inflation economies are compared

another reconciliation between economists and forestry experts olg arguments foresters often claim that the goal of good forest policy is to have a sustained forest yield or even a maximum sustainable yield they also claim that people wish to save a few extra trees for their children this bequest motive is not modelled in the standard approach to the optimal rotation problem in this paper we present a standard version of an overlapping generation model augmented with a simple tree technology we show in particular that the market equilibrium can be dynamically inefficient and that a bequest motive in terms of trees can correct for the overaccumulation of capital that causes the inefficiency the bequest motive also enables us to account for a harvesting intensity varying with age young people typically cut more than elderly people in spite of a perfect capital market

comparison shopping as a simultaneous move game this paper analyzes simultaneous move models of comparison shopping it shows that the equilibria in wilde schwartz 1979 can be rationalized as symmetric mixed strategies in an appropriately defined game in which information acquisition costs are endogenous it also shown that in the simultaneous move version of salop stiglitz 1977 nonexistence of equilibrium is not a problem in fact a variety of forms of equilibria emerge in that model pure strategy mixed strategy and blends of the two copyright 1992 by royal economic society

the harvesting decisions when a standing forest with multiple age classes has value a solution is demonstrated to an infinite horizon discrete time utility model describing the consumption and cutting behavior of a nonindustrial private landowner who is managing a multiple age class forest and who values both consumption derived from harvesting the trees and amenity derived from the standing trees a policy rule is derived to attain a normal forest from any initial age class distribution it is demonstrated that a noncyclical forest allowing a constant periodic harvest is typically not a normal forest therefore an even flow timber harvesting is not tied to the existence of a normal forest forest economics literature has a long tradition of looking at the optimal management of one single stand this tradition goes back to faustmann s work in the nineteenth century faustmann however a characteristic feature in forest management is the existence of and possible interdependencies between multiple age classes stands these interdependencies become especially difficult to ignore when one is dealing with multiple use forest management problems forest economics literature recognizing the feature of multiple stands has two main strains one has been interested in landowner timber and nontimber decisions in the presence of spatial interactions of two or more adjacent stands swallow and wear swallow talukdar and wear koskela and ollikainen the other has incorporated stand or age class dynamics into models describing landowner or timber market behavior this latter literature has modeled optimal behavior either based on timber benefits berck 1976 berck 1979 johansson and l ofgren lyon and sedjo sedjo and lyon mitra and wan 1985 mitra and wan 1986 salo and tahvonen 2002 2003 sohngen mendelsohn and sedjo or both

optimal monetary policy in a cash in advance economy i introduction this paper addresses the issue of optimal monetary policy within a particular general equilibrium model of the monetary transmission mechanism the model analyzed is a member of the recent class of liquidity models of the monetary business cycle 1 these liquidity models are something of a growth industry partly because they are potentially consistent with a monetary equilibrium in which monetary injections drive down nominal rates of interest and stimulate real activity stylized facts supported by evidence presented in for example christiano and eichenbaum 1992 an unexplored question is the role of monetary policy in these models this paper makes an attempt at remedying this deficiency by analyzing optimal monetary policy in a model with liquidity effects as in the liquidity models mentioned above the model analyzed here is constructed by imposing two trading frictions on an otherwise frictionless arrow debreu environment 2 the first is a requirement that all transactions be carried out in a decentralized fashion with the use of cash this friction is the well known cash in advance constraint first suggested by clower 1967 but now quite commonplace in models of monetary equilibrium as in lucas and stokey 1987 and cooley and hansen 1989 i impose this constraint because it is a tractable way of introducing a transactions demand for cash the qualitative results would be unaffected if a more general transactions technology was employed the second friction is unique to the liquidity models i assume that private agents cannot quickly move cash across markets this assumption of sluggish cash flow presumably motivated by transactions costs that are not explicitly modeled implies that cash may not be equally valued across markets with its value in a particular market determined by the amount of cash or liquidity contained in the market this friction introduces the so called liquidity effects on asset prices and real activity the paper proceeds as follows the next section develops the basic model and discusses the effects created by the assumed trading frictions section iii explores optimal monetary policy the nature of the trading frictions introduces a role for activist monetary policy in particular to the extent that the central bank can adjust liquidity more rapidly than the private sector there is a welfare improving role for monetary policy in some cases interest rate smoothing is a good idea while in others optimal policy will increase interest rate variability section iv links the results to the optimum quantity of money literature and offers up a few conclusions ii a model of monetary non neutrality the economy is populated with three types of agents households firms and financial intermediaries there are numerous identical agents of each type so that all behave as atomistic competitors given this assumption i will confine my discussion to a representative agent of each type the representative household is made up of two members a shopper and a worker the shopper s role is to use the household s assets to acquire consumption goods during each period while the worker supplies some portion of the household s time endowment equal to 1 each period to firms in exchange for payment the household s preferences over uncertain consumption and leisure streams are given by e summation of beta sup t u c sub t v 1 l sub t where t 0 to infinity where beta is an element of 0 1 c sub t and l sub t are time t consumption and work effort respectively v is increasing and concave and mathematical expression omitted the expectation is over realizations of the economy wide shocks the expression s sub t is an element of s subset r denotes the state of the world at time t where s is a compact set these states are i i d across time with a distribution function given by

liquidity effects and the monetary transmission mechanism several recent papers provide strong empirical support for the view that an expansionary monetary policy disturbance generates a persistent decrease in interest rates and a persistent increase in output and employment existing quantitative general equilibrium models which allow for capital accumulation are inconsistent with this view there does exist a recently developed class of general equilibrium models which can rationalize the contemporaneous response of interest rates output and employment to a money supply shock however a key shortcoming of these models is that they cannot rationalize persistent liquidity effects this paper discusses the basic frictions and mechanisms underlying this new class of models and investigates one avenue for generating persistence we argue that once a simplified version of the model in christiano and eichenbaum 1991 is modified to allow for extremely small costs of adjusting sectoral flow of funds positive money shocks generate long lasting quantitatively significant liquidity effects as well as persistent increases in aggregate economic activity

real exchange rates trade balances and nominal shocks evidence for the g 7 abstract to identify nominal shocks in structural var models of open economies it is common practice to use purchasing power parity as a long run identifying restriction so that there are no long run effects of nominal shocks on real exchange rates however in some recent open economy intertemporal models with sticky prices nominal shocks can have long run effects on both real exchange rates and trade balances in this paper structural var models for the g 7 are identified in such a way that nominal shocks at least potentially can have long run effects on a country s real exchange rate for the g 7 nominal shocks are found to have a significant long run effect on each country s trade balance over the post bretton woods period we do not have to appeal to hysteresis effects to explain this finding for trade balances since nominal shocks are found to have a significant long run effect on each country s real exchange rate

production function regressions returns to scale and externalities a number of recent papers have used simple linear regressions in an attempt to identify market structure the extent of returns to scale and possible external effects in u s manufacturing industries the results obtained from these regressions have important implications for several branches of modern macroeconomics as a result the macro literature frequently cites specific numerical evidence from caballero and lyons 1992 and hall 1990 which suggests that there are quantitatively significant increasing returns to scale or external effects in u s manufacturing in contrast it is the argument of this paper that this evidence is not convincing the most robust evidence suggests that the typical u s manufacturing industry displays constant returns with no external effects on the other hand there is significant heterogeneity across industries

terms of trade shocks and the balance of trade there is a harberger laursen metzler effect abstract according to the harberger laursen metzler hlm effect an exogenous increase in the terms of trade faced by a small open economy leads to an improvement in that country s trade balance in this paper structural vector autoregression techniques are used to investigate whether there is any systematic pattern in the responses of the trade balance to terms of trade shocks for a large number of small open economies two important results emerge first there is strong support in the data for the existence of an hlm effect second the response of the trade balance and real income to a terms of trade shock implied by the structural vector autoregression model are strongly consistent with those reported by mendoza 1995 from simulating a particular dynamic stochastic equilibrium model of a small open economy

multiple equilibria and persistence in aggregate fluctuations this paper explores the impact of incomplete markets and strong complementarities on the time series properties of aggregate activity we consider an economy which consists of a large number of industries whose production functions both are nonconvex and exhibit localized technological complementarities the productivity of each industry at t is determined by the production decisions of technologically similar industries at t 1 no markets exist to coordinate production decisions this feature implies that aggregate output dynamics for the model are quite different from those predicted by the associated arrow debreu economy first multiple stochastic equilibria exist in aggregate activity these equilibria are distinguished by differences in the mean and the variance of output second output movements are persistent as aggregate productivity shocks indefinitely affect real activity by shifting the economy across equilibria as a result the model can exhibit periods of boom and depression this abstract was borrowed from another version of this item

decomposing learning by doing in new plants the paper examines learning by doing in the context of a production function in which the other arguments are labor human capital physical capital and vintage as a proxy for embodied technical c

wage stickiness and the non neutrality of money a cross industry analysis abstract the paper provides an empirical test of sticky wage models of business fluctuations by focusing on industry level cross sectional implications that emerge this breaks the observational equivalence existing at the aggregate level between rational expectations long term contracting and imperfect information models the specific implication tested is whether output responses to nominal disturbances industry phillips curve slopes are inversely related to wage indexation elasticities the phillips curve slopes are found to vary across industries for the canadian economy but bear no relationship to indexation elasticities casting doubt on the role of nominal wage rigidity in generating the observed non neutrality of money

delay and cycles when the profitability of investment depends on the general level of economic activity entrepreneurs have an incentive to delay investments during a recession endogenous delay thus prolongs the recovery from a recession and heightens the effect of the boom this paper describes a dynamic model that exhibits both delay and cycles and develops methods for analysing the role of delay in propogating business cycles a number of interesting characteristics of the cycle are revealed first the effect of delay is asymmetric it lengthens the recovery but not the downturn second delay can increase the amplitude and typically reduces the frequency of the cycle third it can reduce the average level of activity but it achieves this effect by prolonging the recession rather than by reducing the amplitude of the cycle the welfare effects of delay are ambiguous however

the liquidity effect and money demand abstract i suggest a liquidity effect model in which financial intermediation costs are determined by aggregate economic activity an expansionary monetary shock leads to a persistent contraction in the loan deposit rate spread a persistent liquidity effect and a persistent real expansion a feature of this expansion is that nominal prices respond sluggishly to monetary shocks as an equilibrium outcome

the long run relationship between inflation and output in postwar economies abstract we investigate the relationship between inflation and real output in a large sample of postwar economies our methodology is to use a structural vector autoregression to estimate the response of the level of real output to permanent inflation shocks separately for each country we find that a permanent shock to inflation is not associated with a permanent movement in the level of real output for most countries in our sample the main exceptions are certain low inflation countries in which permanent inflation shocks permanently increase the level of output we also find that permanent inflation shocks do not permanently influence real output growth rates in our sample

taxation bequests and short and long run timber supplies an overlapping generations problem this paper uses an overlapping generations model with one sided altruism to study the effects of several forest taxes that target bequests and affect timber supply unlike previous work we investigate bequests and timber supply in both the short and long run when bequests are costly e g taxed the landowner s problem is examined in the short run while the government s problem is examined in the long run assuming the existence of a steady state we also consider taxes targeting harvests growth savings and bequests several new results are established concerning the interactions of taxes that might be used by a government to alter short and long run forest capital stocks i the presence of a forest bequest tax affects the neutrality of harvest tax in both the short and long run ii in the long run the bequest tax decreases bequests and timber supplies when the bequest tax is not present the capital income tax is neutral with respect to bequest and timber supply while the harvest tax is neutral only if forest productivity is also not taxed finally iii in the short run the substitution and total effects of taxes in landowner decisions generally depend on the presence of the bequest tax the results have implications for pigouvian tax design and second best tax choice

labour markets liquidity and monetary policy regimes dans leur etude les auteurs elaborent un modele d equilibre du mecanisme de transmission de la politique monetaire qui fait ressortir les elements de friction relatifs a l acquisition d information sur le marche de la monnaie et a la recherche d emploi

strategic complementarity in business formation aggregate fluctuations and sunspot equilibria the extent to which changes in beliefs can be important factors in initiating economic fluctuations has been a prominent area of investigation for macroeconomists the notion that beliefs about the future influence current decisions is a property of almost all dynamic economic systems the more challenging task is identifying economic environments in which changes in beliefs alone influence current choices in such a way that the variations in beliefs are self fulfilling because the resulting fluctuations arise in the absence of variations in fundamental variables such as preferences and technology they are often termed sunspot equilibria apart from suggesting that instability of expectations may be a distinct source of cyclical volatility sunspot equilibria may also explain why apparently small disturbances in fundamentals lead to large change in macroeconomic aggregates in this study we demonstrate the possibility of sunspot equilibria in an overlappinggenerations economy characterized by a plausible form of strategic complementarity as more agents enter as producers in any particular sector of the economy they create an incentive for agents to enter as producers into other sectors as well 2 the basis for this

energy consumption real income and temporal causality results from a multi country study based on cointegration and error correction modelling techniques abstract unlike previous studies on the causal relationship between energy consumption and economic growth this paper illustrates how the finding of cointegration i e long term equilibrium relationship between these variables may be used in testing granger causality based on the most recent johansen s multivariate cointegration tests preceded by various unit root or non stationarity tests we test for cointegration between total energy consumption and real income of six asian economies india pakistan malaysia singapore indonesia and the philippines non rejection of cointegration between variables rules out granger non causality and imples at least one way of granger causality either unidirectional or bidirectionial secondly by using a dynamic vector error correction model we then analyse the direction of granger causation and hence the within sample granger exogeneity or endogeneity of each of the variables thirdly the relative strength of the causality is gauged through the dynamic variance decomposition technique by decomposing the total impact of an unanticipated shock to each of the variables beyond the sample period into proportions attributable to shocks in the other variables including its own in the bivariate system results based on these tools of methodology indicate that while all pair wise relationships shared common univariate integrational properties only relationships for three countries india pakistan and indonesia were cointegrated for these countries temporal causality results were mixed with unidirectional causality from energy to income for india exactly the reverse for indonesia and mutual causality for pakistan the vdcs were not inconsistent with these results and provided us with an additional insight as to the relatively more dominant direction of causation in pakistan simple bivariate vector autoregressive models for the three non cointegrated systems did not indicate any direction of causality significantly in either direction

monetary and financial interactions in the business cycle this paper develops a computable general equilibrium model in which endogenous agency costs can potentially alter business cycle dynamics the model resembles the influential theoretical work of ben bernanke and mark gertler 1989 two sources of shocks are considered productivity shocks and monetary shocks the model is parametrized to match key features of u s aggregate activity the principal result of the analysis is that agency costs add very little to the basic business cycle dynamics copyright 1995 by ohio state university press

imperfect information monopolistic competition and public policy introduction ever since the pioneering work of george stigler 1961 and the provocative survey by michael rothschild 1973 economists have recognized that general equilibrium models yield competitive equilibria only by making strong assumptions about the information available to market participants in response to this difficulty theorists in recent years have developed a family of search equilibrium models that presuppose homogeneity and the absence of price discrimination and which also assume that information acquisition costs are positive for at least a subset of buyers on the basis of these and other assumptions the models attempt to show how price dispersion equilibria can arise solely as a result of the strategies that firms and consumers pursue one author summarized the results if information is costly each small firm obtains market power so that the relevant market structure with imperfect information is not per ect competition but rather monopolistic competition steven salop 1976 p 240

monopolistic competition when price and quality are imperfectly observable consider the symmetric equilibrium of a monopolistically competitive industry in which manufacturers select price and quality to maximize expected profit and consumers maximize utility by conducting costly search among sellers using an optimal sequential search rule consumers search among sellers because i each consumer idiosyncratically evaluates each seller s quality and ii a retailing sector generates variation in the prices consumers pay consumers are handicapped in their search because their observations of firms price and quality levels are noisy an improvement in price information is represented by an increase in the precision with which consumers observe sellers prices similarly an improvement in quality information is represented by an increase in precision with which consumers observe sellers quality levels an improvement of either type of information may increase or decrease welfare the perverse case in which improved price information decreases welfare occurs when price competition among firms becomes so intense relative to quality competition that firms select severely suboptimal levels of quality a consumer searching among monopolistically competitive sellers may have difficulty accurately observing the price and quality of each seller s product he must infer from his prior beliefs and noisy observations the true values of the product s price and quality attributes we show that increasing the precision with which consumers observe an attribute of a product makes the inference problem easier and causes the demand the seller faces with respect to that attribute to become more elastic the equilibrium level of that attribute changes accordingly and since the equilibrium levels of price and quality interact the equilibrium level of the other attribute changes as well these equilibrium effects can be perverse in two ways first if the precision of quality observation is fixed then improvement in the precision of price observation can reduce welfare the chain of causation is this increasing the precision of price observation causes price to fall the resulting smaller price cost margin induces sellers to reduce quality de

the hump shaped behavior of inflation and a dynamic externality we propose a general equilibrium model that explains the empirical evidence of the hump shaped response of inflation to a monetary policy shock the model replaces backward looking indexation a la christiano et al 2005 nominal rigidities and the dynamic effect of a shock to monetary policy journal of political economy 113 1 1 45 with a dynamic externality into the production function of firms the model armed with sticky wages and variable capital utilization has two offsetting effects on real marginal cost over the business cycle first increasing factor prices raise real marginal cost in response to an expansionary monetary policy shock in the intermediate run second a dynamic externality reduces real marginal cost in the short run because it raises productivity in response to an increase in output following the shock overall the resulting short run decrease and intermediate run increase in marginal cost replicate the hump shaped behavior of inflation under purely forward looking price and wage phillips curves

renewable resource use and nonseparable amenity benefits we incorporate amenity benefits into an overlapping generations model with a renewable resource as a factor of production source of amenity benefits and store of value unlike the conventional renewable resource problems studied under the assumption of additive consumption and amenity benefits we let amenity benefits affect the utility of consumers in a nonseparable fashion we examine the role that weights given to consumption and amenities have for harvesting and the resource stock we characterize dynamics and stability of steady state equilibria with a logistic resource growth function we demonstrate in parametric and numerical models that the weights given to consumption and amenities in the utility function matter substantially for the steady state equilibrium stock and its stability and dynamics both conventional saddle point equilibria and indeterminacy with infinite number of equilibria and saddle node bifurcation is possible depending on the weights given to consumption and amenities in addition we show that for each inefficient equilibrium stock there is a unique subsidy rate that can move the economy from an inefficient equilibrium to an efficient one the presence of indeterminacy provides a challenge to resource policies because the system becomes unpredictable therefore expectations and market psychology may play an important role in resource utilization and provision of amenities

the distribution of money balances and the nonneutrality of money recent monetary models with explicit microfoundations are made tractable by assuming that agents have access to centralized markets after one round of decentralized trade given quasi linear preferences this makes the distribution of money degenerate which keeps the models simple but precludes the discussion of distributional effects of monetary policy we generalize these models by assuming two rounds of trade before agents can readjust their money holdings to study a range of new distributional effects analytically we show that unexpected symmetric lump sum money injections may increase short run output and welfare whereas asymmetric injections may increase long run output and welfare

risk aversion learning spillovers and path dependent economic growth abstract each agent j 1 n receives an independent shock influencing her degree of risk aversion then undertakes a risky or safe investment prior investment in related industries reduces the uncertainty the shock history and this intertemporal interaction determine the long run growth rate

dynamic complementarities a quantitative analysis abstract this paper considers the importance of dynamic complementarities as an endogenous source of propagation in a dynamic stochastic economy dynamic complementarities link the stocks of human and organizational capital which are influenced by past levels of economic activity to current levels of productivity we supplement an otherwise standard dynamic business cycle model with both contemporaneous and dynamic complementarities the model is calibrated using estimates of these effects from both micro and aggregate data our quantitative analysis identifies empirically relevant dynamic complementarities as a source of propagation for both technology and taste shocks

forestry and the bequest motive abstract with an overlapping generations model for trees and humans it is shown that in a small open timber producing economy both in a setting where the economy is planned in order to maximize an intertemporal social welfare function and in a decentralized market economy long term forest investments should be evaluated by their net present value this is so provided that the existing generation has some if even very small concern for the well being of the next generation a review of empirical studies among nonindustrial private forest owners in the u s and in sweden gives support to the suggestion that this mechanism based on a tinge of altruism may be more important in promoting long term silvicultural investments than the incentives given by existing land markets

complementarity growth and trade we consider an endogenous growth model with international trade in complemen tary capital goods the model possesses several distinct balanced growth solutions which we classify using stability under adaptive learning some of the equilibria can involve growth rates much higher than others we show that in addition to a small usually positive effect on a given equilibrium an expansion in trade may sometimes yield a much larger sudden jump in growth the small effect on the initial equilibrium may reduce growth if the oppor tunity cost of capital rises very fast as growth accelerates jel classification f12 f1 5 041 complementarit croissance et commerce international les auteurs utilisent un modele de croissance endogene en presence de commerce international de biens capitaux complemen taires le modele possede plusieurs solutions de croissance equilibree distinctes que les auteurs classifient en utilisant des mesures de stabilite avec apprentissage adaptatif certains de ces equilibres peuvent impliquer des taux de croissance plus eleves que d autres ii appert qu une expansion du commerce international en plus d avoir un petit effet habituellement positif sur un equilibre donne peut parfois engendrer une augmentation plus forte et sou daine de la croissance le petit effet sur l equilibre initial peut reduire la croissance si le couit d opportunite du capital augmente rapidement a proportion que la croissance accelere

search financial market frictions and monetary transmission this paper evaluates the implications of search and matching frictions in the financial market for the bank lending channel of monetary policy borrowers and lenders participate in a decentralized loan market for the purpose of establishing long term credit relationships and the provision of loanable funds to productive firms locating credit relationships is costly in terms of time and real resources and the interest rate is negotiated via a bargaining mechanism this structure is incorporated into an otherwise standard monetary business cycle framework and used to study how such frictions in the credit market contribute to explaining the contemporaneous impact and propagation of monetary growth shocks and inflation while anticipated inflation negatively impacts real activity it can also increase loan market participation and the inflow of newly established credit relationships it is shown that i bargaining and costly search mitigates the traditional inflation tax effect of monetary injections and ii the existence of long term lending relations tends to dampen liquidity effects monetary shocks in this environment lead to larger liquidity effects relative to the frictionless case and are capable of generating persistence in the nominal interest rate labor consumption and output it can also explain the excess volatility of credit creation relative to output and the observation that overall credit creation can lead output over the business cycle

business cycle models with endogenous technology this paper compares real and monetary business cycle models with and without endogenous technical change if technology is endogenous the properties of these models change significantly in particular both real and monetary models yield very similar output processes if growth is endogenous and changes in aggregate demand can result in permanent changes in productivity employment and output the effect of depreciation of technology is examined and the pattern of real wage movements over the cycle when money wages are fixed but technology is changing is briefly considered copyright 1990 by american economic association

optimal forest policies in an overlapping generations economy with timber and money bequests abstract this paper studies optimal forest policies in an overlapping generations forest economy with one sided altruism where timber and monetary bequests can be made across generations and forest amenities can be public goods we extend the existing economics literature by demonstrating that timber bequests can dominate money bequests in many situations and that timber bequests may even be operative in dynamically inefficient steady states we also characterize the optimal policy mix which maximizes long run social welfare this policy mix depends on the nature of the steady state equilibrium and whether non landowners have full access to forest stocks to enjoy amenities the results support the argument that bequests and forest stocks must be considered jointly in determining first and second best policies although these are often analyzed in isolation we also show that combinations of taxes and subsidies on harvesting and bequests may be efficient in a range of equilibria the optimal policy mix we characterize in several types of steady states is not consistent with the choices governments typically make in practice

price quality and timing of moves in markets with incomplete information an experimental analysis this paper reports the results of theoretical and experimental analyses of search models of shopping behavior earlier work which dealt with markets for homogeneous goods in which sellers first determined their prices and buyers then decided upon their information acquisition shopping strategies conditional upon the distribution of prices showed that nash equilibria for these markets were good predictions of outcomes of laboratory experiments the authors extend the analysis to markets with heterogeneous goods and allow buyers and sellers to move simultaneously the results of a series of laboratory experiments indicate that the nash equilibria continue to be good predictions in these more realistic settings copyright 1992 by royal economic society

external effects in u s procyclical productivity abstract in this paper we highlight a new dimension of the aggregate procyclical productivity phenomenon we show that estimates of the degree of returns to scale are larger for manufacturing as a whole than for two digit industries since this difference must be due to factors that are only internalized at the most aggregate level we term it an external effect this result rules out explanations based on own input variation such as true increasing returns and unmeasured factor utilization tied to own activity as the sole explanations for aggregate procyclical productivity we explore several potential explanations of this external effect

exports investments and economic development of pre accession countries of the european union an empirical investigation of bulgaria and romania this paper attempts to analyse the relationship between exports investments and economic development in two pre accession countries of the european union bulgaria and romania for investigation of this relationship a multivariate autoregressive var model is used the results of cointegration analysis showed that there is one cointegrated vector among exports investments and economic growth for the two countries granger causality tests based on error correction models ecm indicated that there is a strong granger causal relation between economic growth and exports as well as between investments and exports for the two countries in addition economic development and capital accumulation in an economy seem to have just as much of an influence on exports as exports have on capital accumulation and economic development

indivisible labor lotteries and equilibrium abstract this paper considers an economy where labor is indivisible and agents are identical although the discontinuity in labor supply at the individual level disappears as a result of aggregation it is shown that indivisible labor has strong consequences for the aggregate bahavior of the economy it is also shown that optimal allocations involve lotteries over employment and consumption

using game theory to model competition the article is an exposition of the basic concepts of noncooperative game theory and their application to advertising product and price competition

indivisible labor and the business cycle abstract a growth model with shocks to technology is studied labor is indivisible so all variability in hours worked is due to fluctuations in the number employed we find that unlike previous equilibrium models of the business cycle this economy displays large fluctuations in hours worked and relatively small fluctuations in productivity this finding is independent of individuals willingness to substitute leisure across time this and other findings are the result of studying and comparing summary statistics describing this economy an economy with divisible labor and post war u s time series

the welfare costs of moderate inflations in the recent past the view that a little bit of inflation was good for the economy was widely held the phillips curve in its earlier incarnations implied that moderate inflation was worth tolerating because it would permit lower unemployment this justification for tolerating inflation has long since been abandoned by economists and policymakers because both theory and experience showed it to be false nevertheless one legacy of this era seems to be a fairly widespread tolerance for moderate inflation recently there has been much discussion of removing this inflationary bias by passing legislation that would require the federal reserve to target zero inflation in this paper we examine some of the consequences of achieving that goal we appraise the revenue and welfare costs of policies designed to reduce moderate inflation rates to zero much has been written about why government policies may have an inflationary bias in this paper we don t address the issue of what motivates governments to inflate implicit in our analysis however is the notion that one important motive for inflation is the revenue raising potential of the inflation tax it would be difficult to argue that the inflation tax constitutes an important revenue source for the united states one indirect and very imperfect measure of this would be contributions by the federal lleserve to the treasury in recent years those rebates have amounted to

endogenous business cycle propagation and the persistence problem the role of labor market frictions contrasting sharply with a recent trend in dsge modeling we propose a business cycle model where frictions and shocks are chosen with parsimony the model emphasizes a few labor market frictions and shocks to monetary policy and technology the model estimated from u s quarterly postwar data accounts well for important differences in the serial correlation of the growth rates of aggregate quantities the size of aggregate fluctuations and key comovements including the correlation between hours and labor productivity despite its simplicity the model offers an answer to the persistence problem chari et al 2000 that does not rely on multiple frictions and adjustment lags or ad hoc backward looking components we conclude modern dsge models need not embed large batteries of frictions and shocks to account for the salient features of postwar business cycles

the federal funds market excess reserves and unconventional monetary policy abstract following the bankruptcy of lehman brothers interbank borrowing and lending dropped whereas reserve holdings of depository institutions skyrocketed as the fed injected liquidity into the u s banking sector this paper introduces bank liquidity risk and limited market participation into a real business cycle model with ex ante identical financial intermediaries and shows in an analytically tractable way how interbank trade and excess reserves emerge in general equilibrium investigating the role of the federal funds market and unconventional monetary policy for the propagation of aggregate real and financial shocks i find that federal funds market participation is irrelevant in response to standard supply and demand shocks whereas it matters for uncertainty shocks i e mean preserving spreads in the cross section of liquidity risk liquidity injections by the central bank can absorb the effects of financial shocks on the real economy although excess reserves might increase and federal funds might be crowded out as a side effect

indeterminacy and increasing returns abstract we investigate properties of the one sector growth model with increasing returns under two organizational structures capable of reconciling the existence of aggregate increasing returns with competitive behavior by firms the first involves input externalities the second involves monopolistic competition we show for parameters in close accord with recent literature on real business cycles that the model displays an indeterminate steady state that can be exploited to generate a model of business fluctuations driven by self fulfilling beliefs in our first class of models growth is generated by exogenous increases in factor productivity in the second class the marginal product of capital is large enough for endogenous growth journal of economic literature classification numbers e00 e3 o40

the cross industry effects of unanticipated money in an equilibrium business cycle model abstract this paper examines the differential real effects of monetary policy across industries the purpose is to test whether these differential effects can be accounted for by an incomplete information rational expectations model of the business cycle in the lucas barro tradition such a model implies a positive relation across markets between the variability of market specific shocks and the reduced form output effect of a monetary shock this proposition is tested using industry level post war u s data and support is found the exploration also uncovers other interesting industry level and aggregate results

liquidity exchange rates and business cycles abstract this paper presents a two country two good two currency model to study the role of liquidity effects in exchange rate determination and the international transmission of economic fluctuations the model provides an exchange rate equation which is different from the simple purchasing powerparity law of exchange rate determination both monetary injections and real disturbances can lead to exchange rate fluctuations and comovements of interest rates prices and output of the two economies whether the covariances of variables in the two countries are positive negative or zero depends critically upon the substitutability of the two consumption goods in consumers preferences

inflation and productive activity in a multiple matching model of money abstract this paper investigates the relationship between money growth inflation and productive activity in a dynamic general equilibrium multiple matching framework where trade frictions are manifested by limited consumption variety productive activity and matching in the goods market are endogenized by a time allocation decision of work and search effort we find that a high degree of complementarity between participation in the labor and goods markets creates a channel by which inflation can positively influence production and output this feature arises when household preferences for consumption variety is sufficiently large and it can also lead to the multiplicity of monetary equilibria

uncertainty and shopping behaviour an experimental analysis this paper reports experimental tests of three search equilibrium models these models which differ only in the search strategies available to the buyers have qualitatively different predictions that is equilibria price distributions single price equilibria at the competitive price and at the monopoly price and two price equilibria the experimental outcomes generally were consistent with the models predictions this suggests that debate on the utility of this class of models should shift to the realism of the models assumptions rather than focus on their ability to characterize market outcomes also since the basic models have been validated the project of analyzing experimentally the results of relaxing some of their assumptions seems worthwhile

liquidity loanable funds and real activity abstract this paper develops a general equilibrium model of two traditional explanations of the monetary black box linking money and real activity the liquidity effect and the loanable funds effect these effects are modeled with a monetary production economy in which central bank injections of cash are funnelled into the economy through the credit market since only borrowers have direct access to the newly injected cash monetary injections cause nominal interest rates to fall if firms are borrowers then monetary injections also increase current and future real activity

money and exchange rates in the grossman weiss rotemberg model abstract we analyze the impact of monetary policy on inflation interest rates and exchange rates in a model with segmented asset markets developed by grossman and weiss 1983 and rotemberg 1984 1985 we find parameters for which real and nominal exchange rates in this model are 1 much more volatile than interest rates inflation rates and money growth rates 2 highly correlated with each other and 3 highly persistent while this model fails to match the data in other important respects it illustrates a potentially useful approach to modelling exchange rate behavior

monetary policy regimes and beliefs this paper investigates the role of beliefs over monetary policy in propagating the effects of monetary policy shocks within the context of a dynamic stochastic general equilibrium model in this model monetary policy periodically switches between low and high money growth regimes when individuals cannot observe the regime directly they must draw inferences over regime type based on historical money growth rates the authors show that for an empirically plausible money growth process beliefs evolve slowly in the wake of a regime change as a result their model is able to capture some of the observed persistence of real and nominal variables following such a regime change

business cycles in international historical perspective business cycle models seek to answer the question of why economies go through cycles of recession and recovery or boom and bust any theory of the business cycle makes two sorts of claims what shocks are most important in disturbing the economy and what economic structure is necessary for propagating these shocks for example one common explanation of business cycles begins with monetary shocks and then seeks to explain why monetary shocks are not purely neutral as neoclassical theory would have it and instead have real effects at least in the short term early models in this vein were often implicitly or explicitly based on the proposition that markets do not clear continuously early equilibrium real business cycle theories instead emphasized the importance of real shocks especially to technology which may cause socially efficient fluctuations even when markets are always in equilibrium more recent models have attempted to marry the equilibrium approach to macroeconomics with the substantive keynesian ideas that money is not neutral and that economic fluctuations are costly new keynesian theories of the business cycle admit the possibility of a number of economic shocks including monetary and technology shocks but then focus on explaining how nominal price rigidities within the economy can turn these shocks into recessions or booms other models show that business cycles driven by keynesian animal spirits are consistent with rigorous microfoundations and rational expectations seeking empirical evidence for and against these various approaches we turn business cycle theories loose on perhaps the greatest macroeconomic laboratory

the effects of budget deficit on national saving in the oecd abstract in this paper we estimate a structural var using a panel of oecd countries which includes national saving and budget deficit both as the ratio to gdp to test the ricardian equivalence hypothesis in this framework we separate saving and deficit movements into two types of shocks associated with structural parameters of these economies our results suggest that ricardian equivalence did not work in our sample of oecd countries since private saving compensated only a small fraction budget deficit this supports the interpretation that the large budget deficits have been a very important factor behind the significant increase in real interest rates in the eighties and early nineties

production growth and business cycles ii new directions abstract this paper outlines new directions for investigations of real business cycle models consideration of stochastic growth of exogenous and endogenous forms analysis of suboptimal outcomes arising due to externalities of distorting taxes and implications of labor market heterogeneity

the relation between price and marginal cost in u s industry an examination of data on output and labor input reveals that some u s industries have marginal cost well below price the conclusion rests on the finding that cyclical variations in labor input are small compared with variations in output in booms firms produce substantially more output and sell it for a price that exceeds the costs of the added inputs the paper documents the disparity between price and marginal cost where marginal cost is estimated from annual variations in cost it considers a variety of explanations of the findings that are consistent with competition but none is found to be completely plausible

monopolistic competition and the effects of aggregate demand how important is monopolistic competition to an understanding of the effects of aggregate demand on output we ask the question at three levels can monopolistic competition by itself explain why aggregate demand movements affect output can it together with other imperfections generate effects of aggregate demand in a way that perfect competition cannot if so can it give an accurate account of the response of the economy to aggregate demand movements the answers are no yes and yes

sticky price and limited participation models of money a comparison abstract we provide new evidence that models of the monetary transmission mechanism should be consistent with at least the following facts after a contractionary monetary policy shock the aggregate price level responds very little aggregate output falls interest rates initially rise real wages decline by a modest amount and profits fall we compare the ability of sticky price and limited participation models with frictionless labor markets to account for these facts the key failing of the sticky price model lies in its counterfactual implications for profits the limited participation model can account for all the above facts but only if one is willing to assume a high labor supply elasticity 2 percent and a high markup 40 percent the shortcomings of both models reflect the absence of labor market frictions such as wage contracts or factor hoarding which dampen movements in the marginal cost of production after a monetary policy shock 1997 elsevier science b v

oil price shocks and employment the case of ohio coal mining economic theory suggests that oil price shocks will have an impact on employment in local coal markets however theory is silent on both the absolute and relative magnitudes based on vector autoregressive models we find that oil price shocks and therefore opec policies have significant impacts on ohio coal mining employment our study indicates that oil price shocks have larger impacts on ohio coal mining employment than do shocks to coal prices or coal wages our study is unusual in that we have examined the impact of oil price shocks on employment in a specific industry

fair trades by trade fairs information providing institutions under monopolistic competition it is a standard result of search theory that the optimal reservation supply price e g wage is negatively correlated to search costs this paper applies the inverse relationship between demand prices and limit prices to the analysis of an hitherto unexplored topic trade fairs trade fairs bloomed during the middle ages and early trade based capitalism and survived for centuries in last decades their growth became sustained they attract every year hundreds of thousands of exhibitors and tens of millions of visitors

evidence on macroeconomic complementarities this paper provides empirical evidence on macroeconomic complementarities a restriction on the nature of interaction between individuals in a multiagent setting these models imply that activities across agents will be positively correlated that discrete decisions will be synchronized and that disturbances will be magnified and propagated the paper shows that these implications are consistent with aggregate observations as well as some microeconomic evidence further looking at certain historical episodes such as the national industrial recovery act as well as seasonal fluctuations provides additional support for models with macroeconomic complementarities copyright 1996 by mit press

armen alchian s contribution to macroeconomics i introduction this essay examines alchian s contribution to the theory and practice of macroeconomics we have the task of reviewing alchian s contributions in an area that represents only a tiny fraction of his body of work citations to his work on the theory of the firm greatly outnumber those on money and inflation nevertheless we find that many of the major developments in macroeconomics in the last two decades follow paths that were pointed out in the late 1950s and early 1960s by armen alchian much of it in collaboration with reuben kessel alchian s ideas about macroeconomics were developed in a fertile environment at ucla in conversations with colleagues such as karl brunner and jack hirshleifer as well as with graduate students such as allan meltzer and rachael and ted balbach a signature of alchian s work was his great ability to clarify the issues he was careful to distinguish the effects of money versus real shocks of anticipated versus unanticipated inflation and to work through the impact of an event to the general equilibrium consequences he understood that real world problems such as incomplete information might explain apparently noneconomic behavior but unlike many macroeconomists of that time he did not abandon microeconomic principles when explaining nominal real interactions alchian s views were a clear contrast to those of prominent macroeconomists of the day who argued that aggregate monetary policies could not be used to stabilize the price level at full employment because of asymmetric rigidities in markets that prevented the downward adjustment of any nominal price as part of the process of adjusting relative prices 1 the conventional wisdom of the day led to policies that ultimately caused two decades of accelerating and costly inflation both the rational expectations revolution and developments in modeling the microfoundations of business cycles were a reaction to this experience and to the apparent failure of standard macroeconomic analysis alchian s 1970 work on the effect of private information was one of the original articles in this microfoundation literature although he used a narrative approach rather than the highly structured mathematical models available to researchers today alchian was more than two decades ahead of the real business cycle economists in asking researchers to explore economic explanations fully before adopting explanations based on market failure money illusion and irrational behavior this paper is organized in four parts the first part describes alchian s work involving the fundamental role of money in society king and plosser 1986 93 wrote but in the explosion of formal modeling of monetary economies in the postwar period brunner and meltzer 1971 and alchian 1977 stand nearly alone in stressing the idea that monetary arrangements economize on the information production that would otherwise be necessary to mitigate problems of moral hazard in the exchange of commodities the second part discusses alchian and klein s work on the measurement of inflation this measurement problem appears to be more obvious when inflation is low and the variance of price indexes is dominated by real factors this work was generally neglected at the time it was written perhaps because inflation accelerated so rapidly that the real factors became less important now that inflation has declined to moderate levels the measurement problems are resurfacing the third part of the paper documents alchian s insight into the problems and intellectual developments that followed the erratic inflation policies of the u s government in the 1960s and 1970s in a 1962 journal of political economy article he and reuben kessel set forth a description of the events that occur as an economy shifts from one steady state inflation regime to another this work revealed an understanding of the importance of credibility for the policymaker that was missing from much of the writing about macro policymaking in the subsequent three decades

demand and supply shocks in italy an application to industrial output abstract we investigate the impact of three different kinds of disturbances on industrial output in italy they originate respectively in aggregate demand technology and the labour supply we first illustrate the theoretical restrictions which permit identification of the three shocks then econometric identification is achieved by extending the blanchard and quah 1989 the american economic review 79 pp 655 673 procedure to a multivariate case our main conclusion is that output variability is significantly affected by technological shocks at all frequencies labour supply disturbances are also relevant while demand shocks have a minor impact on the series although they act in the expected direction therefore the short run behaviour of industrial production is largely explained by supply side shocks

anticipated inflation and the capital stock in a cash in advance economy abstract an economy is constructed in which the steady state capital stock is inversely related to the rate of inflation as a result that is directly opposite the usual conclusion

on measuring the welfare cost of business cycles lucas 1987 argues that the gain from eliminating aggregate fluctuations is trivial following lucas a number of researchers have altered assumptions on preferences and found that the gain from eliminating business cycles are potentially very large however in these exercises little discipline is placed on preference parameters this paper estimates the welfare cost of business cycles allowing for potential time non separabilities in preferences where discipline is placed on the choice of preference parameters by requiring that the preferences be consistent with observed fluctuations in a model of business cycles that is a theoretical real business cycle world is constructed and the representative agent is then placed in this world the agent responds optimally to exogenous shocks given the frictions in the economy the agent s preference parameters along with other structural parameters are estimated using a bayesian procedure involving markov chain monte carlo methods two main results emerge from the paper first the form for the time non separability estimated in this paper is very different than the forms suggested and used elsewhere in the literature second the welfare cost of business cycles is close to lucas s estimate

is rising rts a figment of poor data abstract while using detailed firm level data from the private business sector this study identifies two empirical puzzles i returns to scale rts parameter estimates rise at higher levels of data aggregation and ii estimates from the firm level suggest decreasing returns to scale the analysis shows that although consistent with rising estimates neither entry exit nor the basu fernald returns to scale in u s production estimates and implications journal of political economy 105 249 283 aggregation bias effect drives this result rather rising and too low rts estimates seem to reflect a mixture of random errors in factor inputs at the firm level it turns out in fact that a 7 5 10 percent error in labor hours worked can explain both puzzles

what do residuals from first order conditions reveal about dge models the first order condition foc associated with labour in many dynamic general equilibrium models involves only current period variables residuals constructed from this foc are inconsistent with aggregate us data in that they are very large and highly persistent the persistence suggests that models which introduce dynamic terms in the labour foc may be more consistent with the data three such models one with learning by doing one with habit formation and one with labour adjustment costs confirm that they can reduce the persistence in the residuals making the models more consistent with the joint dynamics of consumption output and hours

growth effects of taxation under altruism and low elasticity of intertemporal substitution an increase in the tax rate on capital income may raise the rate of economic growth when the elasticity of intertemporal substitution is low and intergenerational transfers are absent since the strength of the bequest motive depends on tax rates this paper provides conditions under which taxing capital income and then reducing the labour income tax is more growth enhancing than the classical policy of zero taxes on capital income and vice versa this paper analyses the effects of different taxes on the rate of economic growth we consider an economy in which public spending is a fixed fraction of the gnp and the government can obtain revenues from proportional taxes on both labour and capital income obviously the growth effects of these two instruments will depend on the assumptions made about the economic environment in the standard overlapping generations olg model with production diamond 1965 an increase in capital income taxes allows a reduction in labour income taxes and thus agents will enjoy more income when they are young since in the olg model young agents must purchase the total stock of capital installed in the next period and saving is increasing in young income higher taxes on capital income may lead to faster capital accumulation in order to complete the argument we must ensure that the associated decrease in the after tax interest rate does not lead to a reduction in saving which would outweigh the previous income effect in other words we need a sufficiently low elasticity of intertemporal substitution the argument is thus similar to the one of jones and manuelli 1992 who have already pointed out that if the technological environment makes sustained growth feasible then taxing the old agents and subsidising the young ones may increase the rate of economic growth however the situation is completely different if we consider instead an economic environment in which the life cycle considerations are absent for instance in endogenous growth models with a representative agent or dynasty and infinite life span an increase in the capital income tax rate typically translates into lower growth see for instance sato 1967 feldstein 1974 stiglitz 1978 and the more recent contributions of lucas 1990 and rebelo 1991 a way to give a unified treatment to these two alternative models is by means

production inflexibilities and the cost channel of monetary policy this article shows how the existence of production inflexibilities in the form of capacity utilization constraints conditions the magnitude of the response of macroeconomic variables to a money supply stimulus capacity is modeled under explicit microfoundations where the existence of idiosyncratic demand uncertainty generates variable utilization rates across firms in this context money has real effects due to non fisherian effects stemming from limitations in households access to the financial market firms capacity constraints generate a convex aggregate supply curve which is a feature of the economy that has important implications for the conduct of monetary policy

learning by doing and aggregate fluctuations abstract an unresolved issue in business cycle theory is the endogenous propagation of shocks yielding allocations that exhibit the persistence displayed in the data this paper explores the quantitative implications of one propagation mechanism learning by doing whose parameters are estimated using sectoral and plant level observations in the u s which are then integrated into a stochastic growth model with technology shocks we conclude that learning by doing can be a powerful mechanism for generating endogenous persistence moreover learning by doing implies that the employment decision of the representative agent is dynamic which allows a re interpretation of taste shocks or cyclical labor utilization as endogenous labor supply shifts

multiple expectational equilibria under monopolistic competition this paper shows that a monopolistically competitive economy with real investment can have multiple rational expectations equilibria one is associated with entrepreneurs optimistic expectations about future demand another with entrepreneurs pessimism it also shows that an optimistic expectational equilibrium pareto dominates a pessimistic equilibrium an investment subsidy can be beneficial both by reducing the original underinvestment distortion and by changing firms expectations from pessimistic to optimistic the most important assumption is increasing returns to scale and monopolistic competition makes increasing returns consistent with each producer s optimization

regional and sectoral evidence of the macroeconomic effects of labor reallocation a panel data analysis this paper revisits the sectoral shifts hypothesis by examining unemployment fluctuations for 48 u s states over the period 1990 01 2011 12 we develop a panel approach that incorporates dynamics parameter heterogeneity aggregate factors and cross sectional dependence our findings provide support for a positive and significant effect of the employment dispersion index on unemployment this outcome is robust under alternative specifications and measures of employment dispersion the empirical evidence corroborates the presence and relevance of cross sectional dependence and heterogeneity among states the results show that once unobserved common factors and cross state heterogeneity are taken into account labor reallocation has a significant effect on unemployment that is half the size of the estimate when cross sectional dependence is not taken into account

the effects of macroeconomic shocks on sector specific returns the reliance on market and sector specific indexes to evaluate managed portfolios and the popularity of index investing has increased the importance of understanding what leads to market movements how long they may last and how different sectors respond to macroeconomic shocks this research is concerned with how shocks to macroeconomic variables affect five major s p sector specific stock market indexes the paper employs the newly developed econometric technique of generalized impulse response analysis the results identify the various responses of the sectors to unanticipated changes in some key macroeconomic variables asset prices are commonly believed to react sensitively to economic news daily experience seems to support the view that individual asset prices are influenced by a wide variety of unanticipated events and that some events have a more pervasive effect on asset prices than do others chen et al 1986 p 386

common currencies vs monetary independence we study the optimal monetary policy in a two country open economy model under two monetary arrangements a multiple currencies controlled by independent policy makers b common currencies with a centralized policy maker our findings suggest that i monetary policy competition leads to higher long term inflation and interest rates with large welfare losses ii the inflation bias and the consequent losses are larger when countries are unable to commit to future policies iii the welfare losses from higher long term inflation dominates the welfare costs of losing the ability to react optimally to shocks

liquidity and real activity in a simple open economy model abstract this paper analyzes the ability of an open economy version of lucas s 1990 liquidity model to account for properties of international data the focus is on the model s ability to account for exchange rate dynamics and measured effects of monetary policy shocks on exchange rates interest rates and real activities across countries the model generates a prediction that a positive domestic monetary innovation is associated with nominal and real currency depreciations however the model s predictions with respect to nominal and real exchange rate volatilities are low

real business cycles and the animal spirits hypothesis abstract we calibrate a quantitative equilibrium macroeconomic model with an aggregate technology that is subject to increasing returns and show that this model may display fluctuations at business cycle frequencies even when there are no shocks to the fundamentals of the economy these fluctuations are due to the self fulfilling beliefs of investors which we call animal spirits we compare the impulse response functions predicted by our model and by two other more standard models with a four variable vector autoregression on u s data our animal spirits economy is the most successful of the three at matching broad features of the dynamic responses in the data journal of economic literature classification numbers e00 e3 e32

monetary policy in a financial crisis what are the economic effects of an interest rate cut when an economy is in the midst of a financial crisis under what conditions will a cut stimulate output and employment and raise welfare under what conditions will a cut have the opposite effects we answer these questions in a general class of open economy models where a financial crisis is modeled as a time when collateral constraints are suddenly binding we find that when there are frictions in adjusting the level of output in the traded good sector and in adjusting the rate at which that output can be used in other parts of the economy then a cut in the interest rate is most likely to result in a welfare reducing fall in output and employment when these frictions are absent a cut in the interest rate improves asset positions and promotes a welfare increasing economic expansion

the welfare implications of foreign exchange intervention abstract this paper examines the welfare implications of foreign exchange intervention in a two country two currency general equilibrium model with limited participation in financial markets and cash in advance constraints on transactions both sterilized and nonsterilized intervention operations have significant impacts on the allocation of liquidity in international financial markets and therefore affect real economic activities the welfare effects of shocks to monetary policy sterilized and nonsterilized foreign exchange interventions are examined and compared the design of welfare maximizing intervention policy rules is also discussed