Lauderdale, Benjamin E. (2012) Compound poisson-gamma regression models for dollar outcomes that are sometimes zero. Political Analysis, 20 (3). pp. 387-399. ISSN 1047-1987
Full text not available from this repository.Abstract
Political scientists often study dollar-denominated outcomes that are zero for some observations. These zeros can arise because the data-generating process is granular: The observed outcome results from aggregation of a small number of discrete projects or grants, each of varying dollar size. This article describes the use of a compound distribution in which each observed outcome is the sum of a Poisson-distributed number of gamma distributed quantities, a special case of the Tweedie distribution. Regression models based on this distribution estimate loglinear marginal effects without either the ad hoc treatment of zeros necessary to use a log-dependent variable regression or the change in quantity of interest necessary to use a tobit or selection model. The compound Poisson-gamma regression is compared with commonly applied approaches in an application to data on high-speed rail grants from the United States federal government to the states, and against simulated data from several data-generating processes.
| Item Type: | Article |
|---|---|
| Additional Information: | © 2017 Cambridge University Press |
| Divisions: | Methodology |
| Subjects: | J Political Science H Social Sciences > HA Statistics |
| Date Deposited: | 03 Apr 2025 14:36 |
| Last Modified: | 03 Apr 2025 16:03 |
| URI: | http://eprints.lse.ac.uk/id/eprint/127822 |
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