winners and losers in housing markets this paper is a quantitatively oriented theoretical study into the interaction between housing prices aggregate production and household behaviour over a lifetime we develop a life cycle model of a production economy in which land and capital are used to build residential and commercial structures we find that in an economy where the share of land in the value of structures is large housing prices react more to an exogenous change in expected productivity or the world interest rate causing large redistribution effects between net buyers and net sellers of houses changing the financing constraint however has limited effects on housing prices

truth telling and nash equilibria in minimum cost spanning tree models abstract in this paper we consider the minimum cost spanning tree model we assume that a central planner aims at implementing a minimum cost spanning tree not knowing the true link costs the central planner sets up a game where agents announce link costs a tree is chosen and costs are allocated according to the rules of the game we characterize ways of allocating costs such that true announcements constitute nash equilibria both in case of full and incomplete information in particular we find that the shapley rule based on the irreducible cost matrix is consistent with truthful announcements while a series of other well known rules such as the bird rule serial equal split and the proportional rule are not

wealth accumulation over the life cycle and precautionary savings this article constructs and simulates a life cycle model of wealth accumulation and estimates the parameters of the utility function the rate of time preference and the coefficient of risk aversion by matching the simulated median wealth profiles with those observed in the panel study of income dynamics and in the survey of consumer finances the estimates imply a low degree of patience and a high degree of risk aversion the results are used to study the importance of precautionary savings in explaining wealth accumulation they imply that wealth accumulation is driven mostly by precautionary motives at the beginning of the life cycle whereas savings for retirement purposes become significant only closer to retirement

guest editor s introduction to the special issue the evolution of firm capabilities this special issue deals with the question of how it is that over time some firms manage to become successful using their capabilities while other firms do not the articles examine the ways in which firm capabilities emerge develop and change over time and the resulting effects on firm performance conceptual models and analyses based on empirical research deal with market entry and the evolution of firm capabilities adaptation and change in capabilities and heterogeneity of firm capabilities over time within these broad themes specific topics include the role of pre entry experience and initial conditions aspirations and learning dynamic capabilities technological change products and markets mergers and acquisitions and managerial cognition copyright 2000 john wiley sons ltd

household risk management and optimal mortgage choice the portfolio of the typical american household is quite unlike the diversie ed portfolio of liquid assets discussed in e nance textbooks the major asset in the portfolio is a house a relatively illiquid asset with an uncertain capital value the value of the house generally exceeds the net worth of the household which e nances its homeownership through a mortgage contract to create a leveraged position in residential real estate other e nancial assets and liabilities are typically far less important than the house and its associated mortgage contract the importance of housing in household wealth is illustrated in figure i this e gure plots the fraction of household assets in housing and in equities against the wealth percentile of the household poor households appear at the left of the e gure and wealthy households at the right data come from the 1989 and 1998 survey of consumer finances the e gure shows that middle class american families from roughly the fortieth to the eightieth percentile of the wealth distribution have more than half their assets in the form of housing even after the expansion of equity ownership during the 1990s equities are of negligible importance for these households 1

maximum score estimates of the determinants of residential mobility implications for the value of residential attachment and neighborhood amenities abstract this paper uses a semiparametric empirical technique maximum score to estimate the determinants of the decision of low income renters to move out of their dwelling the maximum score estimates prove to be far more precise than probit estimates the estimates are used to show that low income residents highly value remaining in their dwelling in addition these estimates are used to illustrate an alternative method to measure willingness to pay for neighborhood amenities which we argue to be superior to hedonic based wtp measures

housing demand during the boom the role of expectations and credit constraints i use a life cycle model of housing demand to infer expectations about house prices and home equity requirements for the housing boom of the 2000s from observed household choices expectations and credit constraints are separately identified from the intensive and extensive margins of housing demand the main results are that 1 expected price growth was close to average long run growth 2 home equity requirements were lax initially but tightened after the bust and 3 subjective uncertainty about future price growth was large given the option to default on mortgage debt greater price uncertainty leads to higher optimal household leverage

the nature of precautionary wealth abstract this paper uses the panel study of income dynamics to provide some of the first direct evidence that wealth is systematically higher for consumers with predictably greater income uncertainty however the apparent pattern of precautionary wealth is not consistent with a standard parameterization of the life cucle model in which consumers are patient enough to begin saving for retirement early in life wealth is estimated to be far less sensitive to uncertainty than implied by that model instead our results suggest that over most of their working life time consumers behave in accordance with the buffer stock models of saving described in carroll 1992 1997 or deaton 1991 in which consumers hold wealth principally to insulate consumption against near term fluctuations in income

expanding the life cycle model precautionary saving and public policy one of the key puzzles in understanding saving behavior is not so much why people save the title of this session but why people don t save according to the familiar life cycle model households should accumulate wealth to provide for their retirement consumption the surprising result from the data is the sizable fraction of the population who have accumulated so little even among those nearing retirement given that earnings will almost surely decline when households retire such behavior can imply poor living standards for the elderly some might interpret the low wealth accumulation as being evidence of myopia irrationality or a failure of households to enforce mental accounting richard thaler 1994 while others might view the low level of wealth accumulation as evidence of high individual rates of time preference determining the underlying causes of low wealth is crucial for public policies that seek to alleviate low aggregate saving rates in the united states as well as policies that seek to buttress the adequacy of financial resources for the elderly in this paper we outline what we believe to be the causes of why many people do not save we conclude by speculating about government policies that may be most effective at encouraging saving much of the research examining levels of consumption saving and wealth as well as their responsiveness to policy has been done using a life cycle model with the simplifying assumption of perfect certainty alan auerbach and laurence kotlikoff 1987 for example developed a model with 55 overlapping generations of individual lifecycle households each with empirically plausible age earnings profiles and utility parameters and used the model to address tax policy and demographic issues in a regime in which all households are identical within a generation and all generations know future earnings and interest rates more recently a line of inquiry has examined the effects of uncertainty on saving generally in the context of highly stylized models this research has shown that in these models uninsured earnings uncertainty can alter optimal saving behavior in a variety of important ways for a partial review of this precautionary saving literature see hubbard et al 1994 in two recent papers hubbard et al 1993 1994 we have combined these two strands of the literature by examining the implications of a life cycle model of consumption saving and wealth accumulation subject to what we think are the three most important sources of uninsured idiosyncratic risk facing households uncertainty about earnings medical expenses and length of life our intent has been to create a realistic model in which families live for many periods working for part of their lives and retiring later in life to parameterize the uncertainty facing families we estimate tdiscussants christopher carroll federal reserve board john b shoven stanford university laurence kotlikoff boston university

consumer durables and inertial behaviour estimation and aggregation of s s rules for automobile purchases the s s model originally introduced in the study of inventories see arrow et al 1951 scarf 1959 has recently received renewed attention both in the durable consumption and in the investment and labour demand literatures caballero 1993 for instance appeals to these type of models to explain the time series properties of durable expenditure and in particular the persistence or slow adjustment of such a variable in this paper i model the purchase behaviour of automobiles by u s households as an s s rule i estimate a flexible specification of such a rule using a large microeconomic data set and study some of the aggregate implications of this type of inertial behaviour the paper is one of the first attempts at estimating directly the parameters of an s s rule using micro data because of this some of the methodological issues concerning the specification and the estimation of s s rules are relevant for many potential applications furthermore the paper is one of the first to discuss and quantify the aggregate implications of an s s rule estimated on micro data in the presence of non convex transaction costs a full and consistent characterization of individual behaviour is very hard and typically requires strong restrictions grossman and laroque 1991 prove that an s s rule is optimal for a consumption and investment problem under very special circumstances some of their results were extended by eberly 1991 and beaulieu 1993a b eberly 1991 in particular has derived some closed form solutions for durable consumption in the presence of transaction costs while caballero and engel 1994 construct a model of investment where an s s rule is optimal the main problem with these theoretical results is that it is only possible to show optimality of s s rules under very stringent conditions in particular a necessary condition to derive them is that the optimization problem faced by an individual consumer can be reduced to a problem with a single state variable unfortunately as pointed out by bar ilan and blinder 1992 even simple generalizations are extremely difficult to analyse

durable goods an explanation for their slow adjustment at the microeconomic level durable purchases are often discontinuous and relatively large this feature has the potential to explain why aggregate expenditure on durables responds only slowly relative to the frictionless permanent income model to wealth and other aggregate innovations in this paper i develop new results on the problem of dynamic aggregation of stochastically heterogeneous units which help to characterize the connection between microeconomic behavior and aggregate dynamics in the presence of nonconvex adjustment costs using these results and splitting postwar u s aggregate durable purchases into different subcategories and time periods i provide further support for the view that lumpy microeconomic purchases play an important role in explaining the time series behavior of aggregate expenditure on durable goods

a model of housing in the presence of adjustment costs a structural interpretation of habit persistence building on the model of sanford j grossman and guy laroque 1990 this paper provides a model of household consumption and portfolio allocation which incorporates the role of housing as both a consumption good and as a component of wealth the model captures the following features of the household s problem a utility depends probably nonseparably on two distinct goods nondurable consumption and housing b nondurable consumption can be adjusted cost lessly but housing is subject to an adjustment cost c households face housing price risk in the sense that the relative price of housing varies over time and d in addition to the house the household can invest in a wide variety of financial assets this single reasonably tractable model generates testable implications for portfolio allocation risk aversion asset pricing and the dynamics of nondurable consumption because the original grossman and laroque model considers a utility function in which the durable good is the sole argument and thus abstracts completely from nondurable consump tion their analysis cannot address either the potential spillover effects of the adjustment costs of the durable good on the dynamics of nondurable consumption or the implications for portfolio allocation of housing risk arising from variation in the relative price of housing in addition to generating implications for issues on which the original grossman and laroque model was silent the housing model delivers a strikingly different message concerning asset pricing that is in contrast to the grossman and laroque result that the consumption based capital asset pricing model consumption capm fails the housing model implies that the consumptioncapm holds we assume that the household incurs an adjustment cost when altering the holding of the dura ble good or house although financial assets can be bought and sold costlessly consumption of the nondurable good can also be adjusted costlessly when choosing a new house the consumer takes into account the fact that the consumption of housing services will be constant at the new level until the subsequent stopping time when it is again worthwhile to incur the adjustment cost thus the home purchase decision is endogenous and fully rational but because of the adjustment cost infrequent in this continuous time setting the household s decision process has a recursive structure at each instant the household first decides whether it is optimal to sell the house immediately on those rare occasions that it is optimal to incur the adjustment cost the household sells the old house and buys a new one instantaneously if the household decides that it is not optimal to sell the house immediately it then determines its optimal holdings of financial assets and optimal level of nondurable consumption conditional on the current housing stock in essence because of the adjustment costs associated with the durable good the current

distributional implications of government guarantees in mortgage markets we analyze the removal of the credit risk guarantees provided by the government sponsored enterprises gses in a model with agents heterogeneous in income and house price risk we find that wealth inequality increases driven by higher mortgage spreads and housing rents housing holdings become more concentrated foreclosures fall the removal benefits high income households while hurting low and mid income households renters and highly leveraged mortgagors with conforming loans gse reform requires compensating transfers sufficiently high elasticity of rental supply or linking gse reform with the elimination of the mortgage interest deduction

a dynamic model of housing demand estimation and policy implications in the u s macroeconomic policy makers are concerned about how consumers will respond to falling incomes nominal home prices falling income rising mortgage interest rates and tightening credit standards in order to address these questions we estimate and simulate a dynamic structural model of housing demand in the model consumers maximize expected discounted lifetime utility from housing services and a composite consumption good the model allows for realistic features of the housing market including non convex adjustment costs from buying and selling a home and credit constraints from minimum downpayment requirements we use the forward simulation procedure of bajari benkard and levin 2007 to estimate the structural parameters especially the elasticity of substitution between consumption and housing services using data from the panel study of income dynamics given the estimated model parameters we simulate the partial equilibrium consumption and housing and

house prices borrowing constraints and monetary policy in the business cycle i develop a general equilibrium model with sticky prices credit constraints nominal loans and asset prices changes in asset prices modify agents borrowing capacity through collateral value changes in nominal prices affect real repayments through debt deflation monetary policy shocks move asset and nominal prices in the same direction and are amplified and propagated over time the financial accelerator is not constant across shocks nominal debt stabilises supply shocks making the economy less volatile when the central bank controls the interest rate i discuss the role of equity debt indexation and household and firm leverage in the propagation mechanism finally i find that monetary policy should not target asset prices as a means of reducing output and inflation volatility

housing taxation and capital accumulation this paper studies the impact of the preferential tax treatment of housing capital in a dynamic general equilibrium life cycle economy populated by heterogeneous individuals the model includes the main housing tax provisions currently in place in the u s and a minimum downpayment requirement upon purchasing non divisible houses the tax code makes the return on housing capital larger than that on business capital which distorts the lifetime profile and composition of individuals savings the wedge between the two rates of return emanates from the failure to tax imputed rents and is amplified by the presence of mortgage interest deductibility simulations show that individuals at all income levels would rather live in a world where imputed rents are taxed or one where mortgage interest payments are not deductible furthermore distributional effects are much smaller than conventionally believed

are americans saving optimally for retirement we solve each household s optimal saving decisions using a life cycle model that incorporates uncertain lifetimes uninsurable earnings and medical expenses progressive taxation government transfers and pension and social security benefits with optimal decision rules we compare household by household wealth predictions from the life cycle model using a nationally representative sample we find making use of household specific earnings histories that the model accounts for more than 80 percent of the 1992 cross sectional variation in wealth fewer than 20 percent of households have less wealth than their optimal targets and the wealth deficit of those who are undersaving is generally small

a dynamic model of housing demand estimation and policy implications a dynamic model of housing demand using data from the panel study of income dynamics psid we specify estimate and simulate a dynamic structural model of housing demand our model generalizes previous applied econometric work by incorporating realistic features of the housing market including non convex adjustment costs from buying and selling a home credit constraints from minimum downpayment requirements and uncertainty about the evolution of incomes and home prices we argue that these features are critical for capturing salient features of housing demand observed in the psid after estimating the model we use it to simulate how consumer behavior responds to house price and income declines as well as tightening credit these experiments are motivated by the u s recession starting in december of 2007 that saw large falls in home prices large negative income shocks for many households and tightening credit standards in the short run relatively few households adjust their housing stock households respond instead by reducing non housing consumption and reducing wealth because they wish to avoid losing their home and the associated adjustment costs households that adjust in the short run are those hit with a series of bad shocks such as a negative income shock and a home price decline a larger proportion of households do adjust their consumption in the long run increasing their housing stock since housing is less expensive however such changes may occur several years after the shocks listed above

consumption and time use over the life cycle we incorporate home production in a dynamic general equilibrium model of consumption and savings with illiquid housing and a collateralized borrowing constraint the calibrated model explains life cycle patterns of households time use and consumption of different categories documented from the microdata it predicts that the interaction of the labor efficiency profile and the home production technology explains households time use the resulting income profiles the endogenous borrowing constraint and home production account for the initial hump in consumption the complementarity of home hours home input and housing in home production drives the consumption profiles later in the life cycle

moving costs nondurable consumption and portfolio choice the substantial adjustment cost for housing affects nondurable consumption and portfolio allocations as well as the frequency of housing transactions a simple theoretical model roughly calibrated is used to assess the quantitative impact of adjustment costs on those decisions the impact on portfolios is found to be significant suggesting that housing wealth should be useful in empirical studies of portfolio choice the welfare loss from the transaction cost is also substantial the effect on nondurable consumption is small however so adjustment costs can explain only a small part of the equity premium puzzle

consumption over the life cycle facts from consumer expenditure survey data this paper uses consumer expenditure survey data and a seminonparametric statistical model to estimate life cycle profiles of consumption controlling for demographics cohort and time effects we construct age profiles for total and nondurable consumption as well as expenditure patterns for consumer durables special emphasis is placed on the comparison of different approaches to control for changes in demo graphics over the life cycle we find significant humps over the life cycle for total nondurable and durable expenditures changes in household size account for roughly half of these humps bootstrap simulations suggest that our empirical estimates are tight in that standard errors are small

overshooting the savings target temporary migration investment in housing and development summary there are two seemingly competing branches of the literature on saving and duration of stay decisions of temporary migrants one relies on the target saving explanation and the other on utility maximization over a life cycle we attempt to reconcile the two approaches within a framework where a migrant has a well defined savings target in planning to purchase a new home at origin but also chooses the time of return and the consumption path to maximize lifetime utility our analysis highlights the role of property investment and savings repatriation in the relationship between temporary migration and development

the effects of health wealth and wages on labour supply and retirement behaviour this paper estimates a life cycle model of labour supply retirement and savings behaviour in which future health status and wages are uncertain individuals face a fixed cost of work and cannot borrow against future labour pension or social security income the method of simulated moments is used to match the life cycle profiles of labour force participation hours worked and assets that are estimated from the data to those that are generated by the model the model establishes that the tax structure of the social security system and pensions are key determinants of the high observed job exit rates at ages 62 and 65 removing the tax wedge embedded in the social security earnings test for individuals aged 65 and older would delay job exit by almost one year by contrast social security benefit levels health and borrowing constraints are less important determinants of job exit at older ages for example reducing social security benefits by 20 would cause workers to delay exit from the labour force by only three months

the effect of income taxation on consumption and labor supply we estimate the incentive effects of income taxation in a life cycle model of consumption and labor supply without intratemporal strong separability we find that consumption and hours worked are direct complements in utility both increase with a compensated increase in the net wage the compensated net wage elasticity is about 0 3 nearly double estimates for u s men from a linear labor supply specification estimated intertemporal elasticities indicate significant intertemporal smoothing of utility the estimated marginal welfare cost of government revenue is 6 20 which is about half the estimated welfare cost when additivity between consumption and leisure is incorrectly imposed

adjustment of consumers durables stocks evidence from automobile purchases this paper tests an optimal s s rule in household durable purchases and examines directly the resulting aggregate expenditure dynamics the observed decision rule responds to income uncertainty and growth as predicted by an s s model resulting from transactions costs tests against liquidity constraints find that about half the households purchase according to an optimal s s rule aggregating the s s rule over households produces a cross section distribution of durables holdings the empirical distribution is similar to that predicted theoretically as is its response to aggregate shocks furthermore simulations of aggregate expenditure based on the household distribution exhibit dynamics consistent with those observed in the 1980s

housing over time and over the life cycle a structural estimation we estimate a structural model of optimal life cycle housing and nonhousing con sumption in the presence of labor income and house price uncertainties the model postulates constant elasticity of substitution between housing service and nonhousing consumption and explicitly incorporates a housing adjustment cost our estimationts the cross sectional and time series household wealth and housing proles from the panel study of income dynamics 1984 to 2005 reasonably well and suggests an intratemporal elasticity of substitution between housing and nonhousing consumption of 0 487 the low elasticity estimate is largely driven by moments conditional on state house prices and moments in the latter half of the sample period and is robust to different assumptions of housing adjustment cost we then conduct policy analyses in which we let house price and income take values as those observed between 2006 and 2011 we show that the responses depend importantly on the housing adjustment cost and the elasticity of sub stitution between housing and nonhousing consumption in particular compared with the benchmark the impact of the shocks on homeownership rates is reduced but the impact on nonhousing consumption is magnied when the house selling cost is sizable or when housing service and nonhousing consumption are highly substitutable