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.

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.

This paper extends the theory of investment under uncertainty to incorporate fixed costs of investment, a wedge between the purchase price and sale price of capital, and potential irreversibility of investment. In this extended framework, investment is a nondecreasing function of q, the shadow price of installed capital. The optimal rate of investment is in one of three regimes (positive, zero, or negative gross investment), depending on the value of q relative to two critical values. In general however, the shadow price q is not directly observable, so we present two examples relating q to observable variables.