Many dynamic problems in economics are characterized by large state spaces which make both computing and estimating the model infeasible. We introduce a method for approximating the value function of high-dimensional dynamic models based on sieves and establish results for the: (a) consistency,...

This paper uses a dynamic optimization model to estimate the welfare gains of hedging against commodity price risk for commodity-exporting countries. We show that the introduction of hedging instruments such as futures and options enhances domestic welfare through two channels. First, by...

This paper advances the specification and estimation of models of retirement and saving in two earner families. The complications introduced by the interaction of retirement decisions by husbands and wives have led researchers to adopt a number of simplifications to increase the feasibility of...

This paper constructs a structural retirement model with hyperbolic preferences and uses it to estimate the effect of several potential policy changes. Estimated effects of policies are compared under hyperbolic and standard exponential preferences. Sophisticated hyperbolic discounters may...

An enhanced version of a structural model jointly explains benefit claiming, wealth and retirement, including reversals from states of lesser to greater work. The model includes stochastic returns on assets. Estimated with Health and Retirement Study data, it does a better job of predicting...

We consider infinite horizon economies populated by a continuum of agents who are subject to idiosyncratic shocks. This framework contains models of saving and capital accumulation with incomplete markets in the spirit of works by Bewley, Aiyagari, and Huggett, and models of entry, exit and...

Campbell and Cochrane (1999) formulate a model that successfully explains a wide variety of asset pricing puzzles, by augmenting the standard power utility function with a time-varying subsistence level, or "external habit", that adapts nonlinearly to current and past average consumption in the...

We apply numerical dynamic programming to multi-asset dynamic portfolio optimization problems with proportional transaction costs. Examples include problems with one safe asset plus two to six risky stocks, and seven to 360 trading periods in a finite horizon problem. These examples show that it...

We implement a dynamic programming algorithm on a computational grid consisting of loosely coupled processors, possibly including clusters and individual workstations. The grid changes dynamically during the computation, as processors enter and leave the pool of workstations. The algorithm is...

Economic theory assigns a central role to risk preferences. This paper develops a measure of relative risk tolerance using responses to hypothetical income gambles in the Health and Retirement Study. In contrast to most survey measures that produce an ordinal metric, this paper shows how to...