the replacement problem abstract a prototypical vintage capital model of economic growth is developed where the decision to replace old technologies with new ones is modeled explicitly technological change is investment specific depreciation in this environment is an economic not a physical concept the vintage capital economy s balanced growth paths and transitional dynamics are analyzed the transitional dynamics are markedly different from the standard neoclassical growth model

measuring urban economic density agglomeration economies are at the heart of urban economics driving the existence and extent of cities and are central to structural transformation and the urbanization process this paper evaluates the use of different measures of economic density in assessing urban agglomeration effects by examining how well they explain household income differences across cities and neighborhoods in six african countries the paper examines simple scale and density measures and more nuanced ones that capture the extent of clustering within cities the evidence suggests that more nuanced measures attempting to capture within city differences in the extent of clustering do no better than a simple density measure in explaining income differences across cities at least for the current degree of accuracy in measuring clustering however simple city scale measures such as total population are inferior to density measures and to some degree misleading the analysis finds large household income premiums from being in bigger and particularly denser cities over rural areas in africa indicating that migration pull forces remain very strong in the structural transformation process moreover the marginal effects of increases in urban density on household income are very large with density elasticities of 0 6 in addition to strong city level density effects the analysis finds strong neighborhood effects for household incomes overall city density and density of the neighborhood matter

networking off madison avenue known for the key role that networking plays in the operation of agencies where interviews suggest that informal networking among close neighbors is critical to many agencies success networking involves the exchange of ideas and while there is no market place for these ideas exchanges may be more deliberate rather than just marshall s 1890 mysteries of the air type of information spillovers this paper examines the effect on productivity of having more near advertising agency neighborhoods and hence better opportunities for meetings and exchange within manhattan we will show that there is extremely rapid spatial decay in the benefits of having more near neighbors even in the close quarters of southern manhattan a finding that is new to the empirical literature and indicates our understanding of scale externalities is still very limited the finding indicates that having a high density of commercial establishments is important in enhancing local productivity an issue in lucas and rossi hansberg 2002 where within business district spatial decay of spillovers plays a key role we will argue also that in manhattan advertising agencies trade off the higher rent costs of being in bigger clusters nearer centers of action against the lower rent costs of operating on the fringes away from high concentrations of other agencies introducing the idea of trade offs immediately suggests heterogeneity is involved we will show that higher quality agencies are the ones willing to pay more rent to locate in greater size clusters specifically because they benefit more from networking while all 1 the research in this paper was conducted while the authors were census bureau research associates at the boston research data center research results and conclusions expressed are those of the authors and do not necessarily indicate concurrence by the census bureau the paper has been screened to ensure that no confidential data are revealed we acknowledge helpful comments from andrew foster on aspects of the paper and from participants in seminars at brown university lse and the university of toronto

the transatlantic productivity gap is r d the main culprit the literature has pointed to different causes to explain the productivity gap between europe and united states in the last decades this paper tests the hypothesis that the lower european productivity performance in comparison with the us can be explained not only by a lower level of corporate rd however using different estimation techniques the r d coefficients for the us firms always turn out to be significantly higher to see to what extent these transatlantic differences may be related to the different sectoral structures in the us and the eu we differentiated the analysis by sectors the result is that both in manufacturing services and high tech sectors us firms are more efficient in translating their r d investments into productivity increases

agricultural productivity and structural transformation evidence from brazil we study the eects of the adoption of new agricultural technologies on structural transfor mation to guide empirical work we present a simple model where the eect of agricultural productivity on industrial development depends on the factor bias of technical change we test the predictions of the model by studying the introduction of genetically engineered soybean seeds in brazil which had heterogeneous eects on agricultural productivity across areas with dierent soil and weather characteristics we nd that technical change in soy production was strongly labor saving and lead to industrial growth as predicted by the model

growth accounting with investment specific technological progress a discussion of two approaches two approaches taken to the embodiment question are compared and discussed quantitative theory and traditional growth accounting the two approaches give very different estimates for the contribution of investment specific technological advance to economic growth therefore the approach taken matters it is argued that the measures used in traditional growth accounting to gauge the importance of investment specific technological progress have little economic content unlike the measure obtained from quantitative theory

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

the geography of linguistic diversity and the provision of public goods abstract this paper analyzes the importance of local interaction between individuals of different ethnolinguistic groups for the provision of public goods at the national level the conceptual framework we develop suggests that a country s public goods i decrease in its overall ethnolinguistic fractionalization and ii either increase or decrease in its local global ethnolinguistic complementarity a measure of how local interaction affects antagonism towards other groups in the society at large after constructing a 5 km by 5 km dataset on language use for 223 countries we empirically explore these theoretical predictions while overall fractionalization worsens public goods outcomes local interaction mitigates this negative association conditional on a country s overall diversity public goods outcomes are maximized when there are a few large sized groups and the diversity of each location mirrors that of the country as a whole

directed technical change with capital embodied technologies implications for climate policy abstract we develop a theoretical model of directed technical change in which clean zero emissions and dirty emissions intensive technologies are embodied in long lived capital stocks switching from dirty to clean innovation leads to ongoing reductions in the relative costs of producing clean investment goods making them ever cheaper to purchase and so encouraging clean investment at the same time falling replacement costs imply falling asset values consequently continuing innovation in capital embodied clean technologies also generates obsolescence costs which are borne by users of clean capital the negative effect of obsolescence costs on demand for clean investment and consequently on the speed of transition to clean growth has been neglected in the literature on directed technical change we show theoretically and using numerical simulations that optimal policies differ in our model of embodied technological change relative to an otherwise comparable model of disembodied technological change with embodied technologies i optimal emissions taxes start higher and rise faster ii much higher clean research and development subsidies are required to effect the switch to clean innovation and iii climate damages under optimal policies are greater we suggest that more attention should be paid to the role of obsolescence costs in modelling transitional effects of climate policies

cross sectional heterogeneity and the persistence of aggregate fluctuations abstract the microevidence indicates that small firms grow faster than big firms i argue that this relationship between the expected growth rate of a firm and its size may provide a microfoundation for the well known high degree of persistence of shocks to aggregate output the logic goes as follows almost any shock tends to temporarily alter firms incentive to invest in growth thereby leading to a reallocation of firms across size categories if small firms grow faster than big ones the impact effect of the shock on aggregate output is gradually absorbed but as fast growing small firms become big and start to grow at the lower rate of big firms the rate at which the shock is absorbed decreases over the adjustment path as a result shocks are absorbed yet at a very low decreasing rate which induces long memory in aggregate output i argue that this transmission mechanism may reconcile the microevidence with the observed degree of aggregate persistence it requires changes in neither the number of firms in the market nor the rate of technological progress it is merely the result of the cross sectional heterogeneity that we observe in real economies

sensitivity of job destruction to vintage and tenure effects matching models with endogenous job destruction typically deliver excessively volatile job destruction and moderate volatility of vacancies in our model vintage and tenure eects promote the creation of new matches that are temporarily more productive while reducing the survival of temporarily less productive matches this cleansing eect pro duces a counter cyclical in ow into unemployment removes the strong response of job destruction to productivity shocks and generates a downward sloping beveridge curve as in the data the model also generates more volatility in vacancies the job nding rate and labour market tightness

structural change and labor productivity growth in latin american manufacturing industries 1970 96 abstract this paper examines recent changes in the pattern of production specialization attained by latin american manufacturing industries comparing argentina brazil colombia chile and mexico to the united states the paper identifies catching up and lagging behind industries during 1970 96 it considers the evolution of macro and micro forces that affect whether an industry manages to close down the gap with the international technological frontier evidence is presented showing that recent structural reforms did not result in a major discontinuity with the past rather path dependency forces have acted as a major factor explaining differential performance among industries after recent changes in the global incentive regime

learning by doing and investment in training a synthesis of two rival models of the life cycle this paper provides a theoretical synthesis of recent discussions of learning by doing and investment in training as alternative forms of human capital accumulation these theoretical notions relate to essentially different phenomena in particular pace becker and mincer investment in training does not completely encompass learning by doing the paper then develops a model in which human capital accumulation occurs via both training and learning by doing the joint training learning model since it is more general then pure models in which all accumulation occurs via either training or learning avoids certain restrictive and seemingly implausible implications of either kind of pure model however the joint model also has implications that while compatible with stylized facts about the life cycle are sharper than those of either kind of pure model for example the joint model implies that market time and earnings must rise early in the life cycle while neither pure model without corners does so finally the notion of learning by doing provides a rationale for an empirical finding that has recently received attention to the effect that the rate of depreciation of human capital is not constant but rather depends on the extent to which it is used in market activities

technology shocks and job flows we consider a version of the solow growth model where technological progress can be investment specific or investment neutral the labour market is subject to search frictions and the existing productive units may fail to adopt the most recent technological advances technological progress can lead to the destruction of technologically obsolete jobs and cause unemployment we calibrate the model to replicate the high persistence that characterizes the dynamics of firms neutral technology and the frequency of firms capital adjustment we find that neutral technological advances increase job destruction and job reallocation and reduce aggregate employment investment specific technological advances reduce job destruction have mild effects on job creation and are expansionary hence neutral technological progress prompts schumpeterian creative destruction while investment specific technological progress operates essentially as in the standard neoclassical growth model using structural var models we provide support to the key dynamic implications of the model copyright 2007 wiley blackwell

gibrat s law for all cities two empirical regularities concerning the size distribution of cities have repeatedly been established zipf s law holds the upper tail is pareto and city growth is proportionate census 2000 data are used covering the entire size distribution not just the upper tail the nontruncated distribution is shown to be lognormal rather than pareto this provides a simple justification for the coexistence of proportionate growth and the resulting lognormal distribution an equilibrium theory of local externalities that can explain the empirical size distribution of cities is proposed the driving force is a random productivity process of local economies and the perfect mobility of workers

an optimal design of collateralized mortgage obligation with pac companion structure using dynamic cash reserve abstract this paper presents a model for optimally designing a collateralized mortgage obligation cmo with a planned amortization class pac companion structure using dynamic cash reserve in this structure the mortgage pool s cash flow is allocated by rule to the two bond classes such that pac bondholders receive substantial prepayment protection that protection being provided by the companion bondholders the structure we propose provides greater protection to the pac bondholders than current structures during periods of rising interest rates when this class of bondholders faces greater extension risk we do so by allowing a portion of the cash flow from the collateral to be reserved to meet the pac s scheduled cash flow in subsequent periods the greater protection is provided by the companion bondholders exposure to interest loss to tackle this problem we transform the problem of designing the optimal pac companion structure into a standard stochastic linear programming problem which can be solved efficiently moreover we present an extended model by considering the quality of the companion bond and by relaxing the pac bondholder shortfall constraint based on numerical experiments through monte carlo simulation we show the utility of the proposed model

an econometric model of production with endogenous improvement in energy efficiency 1970 1995 the purpose of this paper is to introduce a modification of a standard four input production process where energy is used in an inefficient way due to partly unnecessary waste of energy in this production process r d investment is an additional input in order to improve energy efficiency it closes the gap between energy purchased and energy used effectively the more is invested the less is the waste of energy with the cost and benefit of r d investment incorporated in our model of the firm we analyze the impact of an energy tax on r d effort on output and on the waste of energy the model is implemented empirically by choosing a translog cost function and a set of first order conditions using data for the german chemical industry 1970 1995 in a simulation study based on higher energy prices we found outsourcing as the consequent reaction of the firm more material is used and less of energy labor and capital given the unchanged output level there is no indication of a double dividend in terms of environmental improvement as well as higher demand for labor on the industry level calling for a computable general equilibrium approach in order to answer this open question

firm turnover restructuring and labour productivity in transition the case of poland this article explores the impact of turnover and restructuring on labour productivity in the polish economy over the period 1988 to 1993 changes in aggregate productivity are decomposed into elements corresponding to productivity growth among survivors market share growth by survivors and the contributions of entering and exiting firms the traditional entry and exit effects begin to work as transition to a market economy progresses however initial productivity improvements are due to changes in market shares of the existing firms following the break up of large enterprises regression analysis shows that changes in the firm level productivity are affected by restructuring and a more competitive economic environment

the food problem and the evolution of international income levels in most poor countries large fractions of land labor and other productive resources are devoted to producing food for subsistence needs we show that a model incorporating the food problem can provide new and useful insights into the evolution of international income levels in particular we find that the food problem can explain why some countries started to realize increases in per capita output more than 250 years later in history than others we also show that the food problem has important implications for growth miracles and the speed at which a country converges to its balanced growth path

decomposition of new venture growth into firm age survey period and vintage effects firm data are accumulated on a yearly basis in view of the linear relationship of firm age foundation year survey year the fluctuations of firm data classified by age and period cannot be decomposed into age period and cohort foundation year effects three decomposition methods are briefly reviewed and applied to japanese data on new ventures founded since 1995 regarding sales and employment growth the age effect is the largest with a downward trend and the cohort effect is negligible regarding labour productivity the age effect indicates upward movements and the cohort effect is negligible the reason of the negligible cohort effect is discussed

workers machines and economic growth this paper models technology adoption as replacing workers by machines which perform the same job in the production process the paper shows that such modelling of technology adoption affects significantly the analysis of economic growth this model can explain large and persistent international differences in output levels and growth rates caused by small differences in underlying parameters

financial giffen goods examples and counterexamples abstract in the basic markowitz and merton models a stock s weight in efficient portfolios goes up if its expected rate of return goes up put differently there are no financial giffen goods by an example from mortgage choice we illustrate that for more complicated portfolio problems giffen effects do occur

balanced growth despite uzawa i use an event study approach to present novel evidence on the impact of trade liberalization on firm level profits using the uncertainty surrounding the negotiation and ratification process of the canada united states free trade agreement of 1989 cusfta i estimate the impact of different types of tariff reductions on the abnormal returns of canadian manufacturing firms i find that canadian import tariff reductions lead to lower and reductions in canadian intermediate input tariffs to higher abnormal returns the impact of u s tariff reductions is less clear and depends on the size of the affected firms i also calculate the total profit increase implied by my estimates overall cusfta increased per period profits by around 1 2 this was mainly driven by intermediate input tariff reductions which more than offset the negative effect of canadian import tariff reductions

vintage human capital growth and the diffusion of new technology we develop a model of vintage human capital in which each technology requires vintage specific skills we examine the properties of a stationary equilibrium for our economy the stationary equilibrium is characterized by an endogenous distribution of skilled workers across vintages the distribution is shown to be single peaked under general conditions there is a lag between the appearance of a technology and its peak usage a phenomenon known as diffusion an increase in the rate of exogenous technological change shifts the distribution of human capital to more recent vintages thereby increasing the diffusion rate

productivity and the embodiment of technical progress this survey of the issues involved in the embodiment hypothesis that technical change and productivity can be explained by changes in the quality of inputs into the production process treats the interrelationships of technical change and productivity presents some empirical findings on this subject and discusses some fundamental issues in further studies of embodiment topics covered include the nature of the embodiment hypothesis the vintage model of capital and embodiment in other inputs the use of the embodiment hypothesis to study productivity trends the embodiment hypothesis and the productivity slowdown in the 1970s and 1980s and potential future applications of the embodiment hypothesis

critical survey savings and economic growth in neoclassical theory in neoclassical economics economic growth depends upon savings the paper discusses problems with this conventional view and how these have been tackled from pre solowian authors up to the recent new or endogenous growth theory egt these difficulties became particularly clear with the solow swan model of growth in which the savings rate did not affect the rate of growth in the absence of exogenous circumstances savings would only depress the marginal productivity of capital forcing the economy towards a stationary state the paper interprets egt as an attempt to react to this gloomy theoretical prospect the paper examines various difficulties with this attempt

learning by working in big cities individual earnings are higher in bigger cities we consider three reasons spatial sorting of initially more productive workers static advantages from workers current location and learning by working in bigger cities using rich administrative data for spain we find that workers in bigger cities do not have higher initial ability as reflected in fixed effects instead they obtain an immediate static premium and accumulate more valuable experience the additional value of experi ence in bigger cities persists after leaving and is stronger for those with higher initial ability this explains both the higher mean and greater dispersion of earnings in bigger cities

energy price energy efficiency and capital productivity empirical investigations and policy implications abstract the immediate effect of carbon pricing policy is to raise energy costs which in turn reduces energy consumption either through induced capital under utilization or investments in new energy efficient capital the latter mechanism which implies improvements in energy efficiency is realized in the long run while the former which has implications for capital productivity tends to occur in the short run we employ panel vector autoregressions as well as co integration and error correction techniques to identify these short and long run relationships including their differences across canadian industries

mortgage loan portfolio optimization using multi stage stochastic programming we consider the dynamics of the danish mortgage loan system and propose several models to reflect the choices of a mortgagor as well as his attitude towards risk the models are formulated as multi stage stochastic integer programs which are difficult to solve for more than 10 stages scenario reduction and lp relaxation are used to obtain near optimal solutions for large problem instances our results show that the standard danish mortgagor should hold a more diversified portfolio of mortgage loans and that he should rebalance the portfolio more frequently than current practice

a note on growth accounting with vintage capital abstract we show how growth accounting can be performed in the classic vintage capital model of solow solow r 1956 technical change and the aggregate production function review of economics and statistics the growth in real output can be decomposed into the labor share times the growth of labor plus the gross quasi rents on capital times the saving rate we show that data easily obtained from conventional national income accounts can be used to perform this growth accounting

innovation and firm growth does firm age play a role this paper explores the relationship between innovation and firm growth for firms of different ages we hypothesize that young firms undertake riskier innovation activities which may have greater performance benefits if successful or greater losses if unsuccessful using an extensive spanish community innovation survey sample for the period 2004 2012 we apply panel quantile regressions to study the effect of r d activities on firm growth i e sales growth productivity growth and employment growth our results show that young firms face larger performance benefits from r d at the upper quantiles of the growth rate distribution but face larger decline at the lower quantiles r d investment by young firms therefore appears to significantly riskier than r d investment by more mature firms which suggests some policy implications

economic growth size of the agricultural sector and urbanization in africa this paper uses variations in international commodity prices and rainfall to construct instrumental variables estimates of the within country effect that changes in the size of the agricultural sector and gdp per capita growth have on the urbanization rate for a panel of 41 african countries during the period 1960 2007 the paper s three main findings are that i decreases in the share of agricultural value added lead to a significant increase in the urbanization rate ii conditional on changes in the share of agricultural value added gdp per capita growth does not significantly affect the urbanization rate iii increases in the urbanization rate had a significant negative average effect on gdp per capita growth

spatial wage disparities sorting matters spatial wage disparities can result from spatial differences in the skill composition of the workforce in non human endowments and in local interactions to distinguish between these explanations we estimate a model of wage determination across local labour markets using a very large panel of french workers we control for worker characteristics worker fixed effects industry fixed effects and the characteristics of the local labour market our findings suggest that individual skills account for a large fraction of existing spatial wage disparities with strong evidence of spatial sorting by skills interaction effects are mostly driven by the local density of employment not controlling for worker heterogeneity leads to very biased estimates of interaction effects endowments only appear to play a small role

investment and technical progress models in which the growth rate is exogenous provide no role for government in determining growth in our model growth is associated with investment through externalities from learning by watching rather than with the level of the capital stock presumption of a technical progress function with first increasing and then decreasing returns leads to multiple steady state growth equilibria there is also an explicit role of government policy in setting tax rates on output it follows that two economies with identical structures and stochastic tax policies may exhibit very different growth paths over sustained periods although the stationary distribution of growth rates is the same given the desirability in principle of subsidizing investment various practical methods are considered copyright 1992 by oxford university press

education and economic growth in taiwan a case of successful planning abstract taiwan s education system had three features which were instrumental to its spectacular economic success first it had an infrastructure already built up by 1950 for basic education that extended fairly broadly among the population second a ready supply of highly educated labor arrived in 1949 50 from the mainland to replace the japanese and to begin the process of building the local economy most important the education system was planned to grow in a manner that closely matched the changing requirements of the growing economy the compulsary basic education was raised from six to nine years the secondary level curriculum was shifted more toward vocational fields the supply of university graduates was strictly limited and the university curriculum changed to emphasize science and engineering subjects the levels above basic junior high level were expanded but disproportionately into the private sector so they were not as costly to the government

understanding the city size wage gap in 2000 wages of full time full year workers were more than 30 percent higher in metropolitan areas of over 1 5 million people than rural areas the monotonic relationship between wages and city size is robust to controls for age schooling and labor market experience in this paper we decompose the city size wage gap into various components we propose an on the job search model that incorporates latent ability search frictions firm worker match quality human capital accumulation and endogenous migration between large medium and small cities counterfactual simulations of the model indicate that variation in returns to experience and differences in wage intercepts across location type are the most important mechanisms contributing to the overall city size wage premium steeper returns to experience in larger cities is more important for college graduates while differences in wage intercepts is more important for high school graduates sorting on unobserved ability within education group and differences in labor market search frictions and distributions of firm worker match quality contribute little or slightly negatively to observed city size wage premia in both samples

the quantitative consequences of raising the u s saving rate the authors investigate the consequences of a permanent unphased increase in the u s gross saving rate they find that the sacrifice time the time that elapses until consumption surpasses the value it would have had under the initial saving rate is roughly six years and is insensitive to the percentage increase in the saving rate delta sub s the percentage gain in output at the end of decade the decade gain is roughly 26 of delta sub s while the percentage gain in consumption is roughly 8 of delta sub s the saving rate return the internal rate of return on a permanent increase in the saving rate is roughly 16 and is insensitive to delta sub s copyright 1991 by mit press

the attenuation of human capital spillovers abstract this paper uses 2000 census data to estimate the relationship of agglomeration and proximity to human capital to wages the paper takes a geographic approach and focuses on the attenuation of agglomeration and human capital effects differencing and instrumental variable methods are employed to address endogeneity in the wage agglomeration relationship and also to deal with measurement error in our agglomeration and human capital variables three key results are obtained first the spatial concentration of employment within five miles is positively related to wage second the benefits of spatial concentration are driven by proximity to college educated workers an instance of human capital spillovers third these effects attenuate sharply with distance

a paler shade of green environmental policy under induced technical change conventional wisdom argues that environmental policy is less costly if it induces the development of cleaner technologies in contrast to this argument we show that once the second best nature of actual economies is taken into account the cost of environmental policy may well be larger with induced technical change itc than without thus itc may lower both the emissions reductions and the welfare gains associated with environmental policy in an endogenous policy framework itc may reduce the desired stringency of the policy

economic growth lessons from two centuries of american agriculture this paper reviews the growth experience of u s agriculture over the past two centuries in consonance with the view that growth is determined by the economic environment which consists of the available technology incentives constraints and institutions within this framework the implemented technology is determined jointly with the resource allocation the review covers the role played by resource endowment resource flow technical change and its factor bias and product demand it highlights the importance of the income elasticity of demand and the labor augmentation of the technical change the total factor productivity tfp was almost nil at the beginning of the nineteenth century increasing gradually to the point where it exhausted output growth in the latter part of the twentieth century this pattern is consistent with the postulate emerging from this framework where the tfp is endogenous and determined jointly with growth rather than determining it the more recent performance of u s agriculture is placed within a global perspective in order to generalize the discussion

computers obsolescence and productivity this paper develops a new technique for measuring the effect of computer usage on u s productivity growth standard national income and product accounts nipa measures of the computer capital stock which are constructed by weighting past investments according to a schedule for economic depreciation the rate at which capital loses value as it ages are shown to be inappropriate for growth accounting because they do not capture the effect of a unit of computer capital on productivity this is due to technological obsolescence machines that are still productive are retired because they are no longer near the technological frontier and anticipation of retirement affects economic depreciation using a model that incorporates obsolescence alternative stocks are developed that imply a larger computer usage effect this effect together with the direct effect of increased productivity in the computer producing sector accounted for the improvement in u s productivity growth over 1996 1998 relative to the

taxation and the cost of capital the uk experience since the 1960s the uk has witnessed a series of reforms to its corporation tax system these include the creation of corporation tax as an independent tax in 1965 the gradual introduction of generous capital allowances in the early 1970s the introduction of the partial imputation system in 1973 and stock relief in 1975 and the 1984 reforms which reduced the tax rate and capital allowances and abolished stock relief a number of these reforms were designed with the specific intention of influencing company decisions regarding investment and finance through the real cost of capital

the impact of vintage and survival on productivity evidence from cohorts of u s manufacturing plants this paper examines the evolution of productivity in u s manufacturing plants from 1963 to 1992 we define a vintage effect as the change in productivity of recent cohorts of new plants relative to earlier cohorts of new plants and a survival effect as the change in productivity of a particular cohort of surviving plants as it ages both factors contribute to industry productivity growth but play offsetting roles in determining a cohort s relative position in the productivity distribution recent cohorts enter with higher productivity than earlier entrants did whereas surviving cohorts show productivity increases as they age these two effects roughly offset each other however so there is a rough convergence in productivity across cohorts in 1992 and 1987

machine replacement and the business cycle lumps and bumps this paper explores investment fluctuations due to discrete changes in a plant s capital stock the resulting aggregate investment dynamics are surprisingly rich reflecting the interaction between a replacement cycle the cross sectional distribution of the age of the capital stock and an aggregate shock using plant level data lumpy investment is procyclical and more likely for older capital further the predicted path of aggregate investment that neglects vintage effects tracks actual aggregate investment reasonably well however ignoring fluctuations in the cross sectional distribution of investment vintages can yield predictable nontrivial errors in forecasting changes in aggregate investment

putty clay technology and stock market volatility abstract firms first order conditions imply that stock returns equal investment returns from the production technology much applied work uses the adjustment cost technology which implies that the realized return is high when the investment capital ratio is high this paper derives for an arbitrary stochastic discount factor the investment return implied by the putty clay technology the combination of capital heterogeneity and irreversibility creates a novel channel for return volatility the investment return is high when the ratio of investment to gross job creation is low empirically the putty clay feature helps account for u s stock market data

occupational choice and development abstract the rise in world trade since 1970 has been accompanied by a rise in the geographic span of control of management and hence also a rise in the effective international mobility of labor services we study the effect of such a globalization of the world s labor markets the world s welfare gains depend positively on the skill heterogeneity of the world s labor force we find that when people can choose between wage work and managerial work the worldwide labor market raises output by more in the rich and the poor countries and by less in the middle income countries this is because the middle income countries experience the smallest change in the factor price ratio and where the option to choose between wage work and managerial work has the least value in the integrated economy our theory also establishes that after economic integration the high skill countries see a disproportionate increase in managerial occupations using aggregate data on gdp openness and occupations from 115 countries we find evidence for these patterns of occupational choice

what is different about urbanization in rich and poor countries cities in brazil china india and the united states abstract are the well known facts about urbanization in the united states also true for the developing world we compare american metropolitan areas with analogous geographic units in brazil china and india both gibrat s law and zipf s law seem to hold as well in brazil as in the u s but china and india look quite different in brazil and china the implications of the spatial equilibrium hypothesis the central organizing idea of urban economics are not rejected the india data however repeatedly rejects tests inspired by the spatial equilibrium assumption one hypothesis is that spatial equilibrium only emerges with economic development as markets replace social relationships and as human capital spreads more widely in all four countries there is strong evidence of agglomeration economies and human capital externalities the correlation between density and earnings is stronger in both china and india than in the u s strongest in china in india the gap between urban and rural wages is huge but the correlation between city size and earnings is more modest the cross sectional relationship between area level skills and both earnings and area level growth are also stronger in the developing world than in the u s the forces that drive urban success seem similar in the rich and poor world even if limited migration and difficult housing markets make it harder for a spatial equilibrium to develop

the learning curve and pricing in the chemical processing industries data on 37 chemical products are used to test a number of hypotheses about the learning curve and industrial price behavior the results document a strong and consistent learning effect learning is found to be a function of cumulated industry output and cumulated investment rather than calendar time standard economies of scale appear significant but small in magnitude relative to the learning effect variations in the slope of the learning curve are linked to differences in r d expenditures and capital intensity market concentration is found to be a strong influence on price flexibility and the timing of learningrelated price changes

labor supply with job assignment under balanced growth abstract we consider a competitive equilibrium growth model where technological progress is embodied into new jobs which are assigned to workers of different skills in every period workers decide whether to actively participate in the labor market and if so how many hours to work on the job balanced growth requires that the job technology is complementary with the worker s total labor input on the job which is jointly determined by his skill and his working hours since lower skilled workers can supply longer hours we show that the equilibrium features positive assortative matching higher skilled workers are assigned to better jobs only if differences in consumption are small relative to differences in worker skills when the pace of technological progress accelerates wage inequality increases and workers participate less often in the labor market but supply longer hours on the job this mechanism can explain why as male wage inequality has increased in the us labor force participation of male workers of different skills has fallen while their working hours have increased

decomposing technical change within the conventional neoclassical framework a distinction is sometimes made between productaugmenting and factor augmenting technical change a parallel distinction is commonly made between embodied and disembodied technical change with the former associated with factor and the latter with product augmentation disembodied change is commonly assumed to arise from increases in the stock of knowledge independently of the characteristics of the inputs used while embodied change relates to increases in the efficiency of inputs that is labor skills or the productivity of physical capital unfortunately this distinction is ambiguous changes in the efficiency of the inputs used are usually accompanied indeed made possible by increases in knowledge and conversely increases in the stock of knowledge often favor some inputs more than others including the capital goods of one vintage relative to those of another notwithstanding the ambiguity the concept of embodiment has intuitive appeal and this partly explains the focus on decomposing the sources of technical change that followed solow s 6 seminal paper but by the late 1960s a reader of the literature might have concluded that such decomposition was impossible for with merely time series data on inputs and output product augmenting and factor augmenting technical change are empirically indistinguishable in an important paper hall 3 showed that with data on used equipment prices and the interest rate embodied technical change and the deterioration function can in principle be calculated however the paucity of data on the price of used capital goods has allowed little progress in this direction the new longitudinal research database created by the u s bureau of the census now permits still another approach to the estimation of embodied technical change associated

measuring the cost of capital when taxes are changing with foresight abstract the familiar hall jorgenson 1967 cost of capital perturbation is not a uniquely feasible one because of institutional features of actual tax systems the optimal holding time for an incremental unit of capital will generally be infinite the impossibility of an optimal rule for recapturing excess depreciation allowances on disposal is demonstrated when tax changes are foreseen the error in the traditional measure of cost of capital can become highly significant ignorance of this effect led to underestimates of the extent to which the radical changes to the u k corporation tax in 1984 would affect cost of capital and incentives to forestall planned investment

on endogenizing long run growth this assessment of recent theoretical work on endogenous growth identifies three different engines of long run growth i the asymptotic average product of capital is positive ii labor productivity increases as an external effect of capital accumulation iii there are feedback effects on the cost of accumulating knowledge or innovating a general model encompassing all three is considered and then used to review different proposed determinants of long run growth rates the contribution of endogenous growth theory has been to create a framework in which to explain why economic institutions and policies can have long run effects on growth rates

life expectancy human capital social security and growth we analyze the effects of changes in the mortality rate upon life expectancy education retirement age human capital and growth in the presence of social security we build a vintage growth overlapping generations model in which individuals choose the length of education and the age of retirement and where unfunded social security pensions depend on workers past contributions social security has a positive effect on education but pension benefits favor reductions in retirement age the net effect is that starting from a benchmark case higher life expectancies give rise to lower per capita gdp growth in the presence of social security as the share of the active population is reduced in addition higher social security contribution rates reduce the growth rate of per capita gdp

innovation and productivity growth the puzzle confronting economists has been that the rate of growth of output that was being observed has been much larger than the rate of increase in the principal resources that were being measured it is now clear that this puzzle is of our own making because we have been using measures of capital and labor which had been refined and narrowed in ways that excluded many of the improvements that have been made in the quality of these resources theodore w schultz 1962

the scarring effect of recessions abstract according to the conventional view recessions improve resource allocation by driving out less productive firms this paper posits an additional scarring effect recessions impede the developments of potentially superior firms by destroying them during their infancy a model is developed to capture both the cleansing and the scarring effects a key ingredient of the model is that idiosyncratic productivity is not directly observable but can be learned over time when calibrated with statistics on entry exit and productivity differentials the model suggests that the scarring effect dominates the cleansing effect and gives rise to lower average productivity during recessions