Working Paper: CEPR ID: DP17292
Authors: Victor Aguirregabiria
Abstract: This paper studies identification and estimation of a dynamic discrete choice model of demand for differentiated product using consumer-level panel data with few purchase events per consumer (i.e., short panel). Consumers are forward-looking and their preferences incorporate two sources of dynamics: last choice dependence due to habits and switching costs, and duration dependence due to inventory, depreciation, or learning. A key distinguishing feature of the model is that consumer unobserved heterogeneity has a Fixed Effects (FE) structure -- that is, its probability distribution conditional on the initial values of endogenous state variables is unrestricted. I apply and extend recent results to establish the identification of all the structural parameters as long as the dataset includes four or more purchase events per household. The parameters can be estimated using a sufficient statistic - conditional maximum likelihood (CML) method. An attractive feature of CML in this model is that the sufficient statistic controls for the forward-looking value of the consumer's decision problem such that the method does not require solving dynamic programming problems or calculating expected present values.
Keywords: Structural Dynamic Discrete Choice Models; Dynamic Demand of Differentiated Products; Dynamic Panel Data Models; Fixed Effects; Habits; Switching Costs; Storable Products; Durable Products
JEL Codes: C23; C25; C51; D12
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| last choice dependence (D10) | probability of purchasing a product (C25) |
| duration dependence (C41) | likelihood of purchasing decisions (D91) |
| past purchases (D19) | current buying decisions (D16) |
| time elapsed since last purchase (C41) | current demand (J23) |
| fixed effects model (C23) | identification of utility parameters (L97) |
| CML method (C00) | estimation of parameters (C51) |