Working Paper: NBER ID: w12831
Authors: Alberto Abadie; Alexis Diamond; Jens Hainmueller
Abstract: Building on an idea in Abadie and Gardeazabal (2003), this article investigates the application of synthetic control methods to comparative case studies. We discuss the advantages of these methods and apply them to study the effects of Proposition 99, a large-scale tobacco control program that California implemented in 1988. We demonstrate that following Proposition 99 tobacco consumption fell markedly in California relative to a comparable synthetic control region. We estimate that by the year 2000 annual per-capita cigarette sales in California were about 26 packs lower than what they would have been in the absence of Proposition 99. Given that many policy interventions and events of interest in social sciences take place at an aggregate level (countries, regions, cities, etc.) and affect a small number of aggregate units, the potential applicability of synthetic control methods to comparative case studies is very large, especially in situations where traditional regression methods are not appropriate. The methods proposed in this article produce informative inference regardless of the number of available comparison units, the number of available time periods, and whether the data are individual (micro) or aggregate (macro). Software to compute the estimators proposed in this article is available at the authors' web-pages.
Keywords: Synthetic Control Methods; Comparative Case Studies; Tobacco Control; Proposition 99
JEL Codes: C21; C23; H75; I18; K32
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Proposition 99 (H27) | reduction in tobacco consumption (D18) |
| Proposition 99 (H27) | decline in annual per capita cigarette sales (F61) |
| California's tobacco consumption trends (I12) | synthetic control region (R15) |