Harvard University

Intertemporal preferences are di ¢ cult to measure because \u85nancial payments (e.g., checks in the mail) are not equivalent to consumption ows. We estimate time preferences using a structural bu¤er stock consumption model and the Method of Simulated Moments. The model includes stochastic labor income, liquidity constraints, child and adult dependents, liquid and illiquid assets, revolving credit, retirement, and discount functions that allow short-run and long-run discount rates to di¤er. Data on wealth accumulation and credit card borrowing over the lifecycle identify the parameters in the model. In almost all speci\u85cations we reject the restriction to a constant discount factor (i.e., exponential discounting). Our benchmark estimates imply a short-term discount factor of = 0:35 and a long-term annualized discount factor of = 0:97