MacMillan-CSAP Quantitative Research Methods Workshop: Luke Keele (Penn State), “The Perils of the All Cause Model”
“The Perils of the All Cause Model” LINK TO PAPER
Luke Keele, Associate Professor of Political Science, Penn State University
Abstract: One of the most common identification strategies in political science is selection on observables. Under this strategy, analysts assume that they have observed enough covariates to make treatment status as-if random. Adjustments are then made for observed confounders through statistical methods such as regression or matching. Under adjustment methods such as matching or inverse probability weighting, coefficients for control variables are treated as nuisance parameters and are not directly estimated. This is in direct contrast to regression approaches where estimated parameters are observed for all covariates. Analysts often find it tempting to give a causal interpretation to all the parameters in such regression models, which is not possible under some methods like matching. In this paper, we ask when we can justify interpreting two or more coefficients in a regression model as causal parameters. Using Directed Acyclic Graphs, we show how even if some effects are identified in a regression model, many estimated parameters do not represent causal effects.
Speaker Bio: Luke Keele is an Associate Professor in the political science department at Penn State University. In this capacity, he conducts research on statistical methods for causal inference and American politics. Recent research has focused on regression discontinuity designs based on geography, causal mediation analysis, matching methods, and instrumental variables. He has published work in journals such as Psychological Methods, Statistical Science, and the Journal of the Royal Statistical Society, Series A, Statistics in Medicine, American Journal of Political Science, and American Political Science Review. He received his Ph.D from the University of North Carolina at Chapel Hill and was a post-doctoral research fellow at Nuffield College, Oxford University.