logoPicV1 logoTextV1

Search Results


Below results based on the criteria 'placebo tests'
Total number of records returned: 2

1
Paper
Synthetic Control Methods for Comparative Case Studies: Estimating the Effect of California's Tobacco Control Program
Abadie, Alberto
Diamond, Alexis
Hainmueller, Jens

Uploaded 01-20-2007
Keywords comparative case studies
causal inference
placebo tests
differences-in-differences
program evaluation
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.

2
Paper
How Much is Minnesota Like Wisconsin? States as Counterfactuals
Keele, Luke
Minozzi, William

Uploaded 07-10-2010
Keywords causal inference
voter turnout
placebo tests
research design
Abstract Political scientists are often interested in understanding whether state laws alter individual level behavior. For example, states often alter their election procedures, which can increase or decrease the cost of voting. In this example, it is important to understand whether these changes alter turnout since changes in costs may disproportionally affect those at the margin of voting. Analysts have typically used one of two different regression based research designs to estimate whether changes in state laws increase or decrease turnout. In both instances, voters from states without a change in laws are used as counterfactuals for the voters who experience a change in election law. Here, we carefully examine the assumptions behind both research designs and study their plausibility. Next, we outline a series of research design elements that can be used in addition to the usual designs. These research design elements allow the analyst to better understand the role of unobserved confounders, which is obscured in standard research designs. Using these design elements, we demonstrate that what appears to be clear cut evidence from the usual research designs is often a function confounding. We argue that to truly understand how changes in voting costs alters turnout, a different research design is required. Future work must rely on a research design that makes comparisons among voters who live within the same state. Our work has implications beyond turnout to any investigation of how state level treatments alter individual behavior.


< prev 1 next>
   
wustlArtSci