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An Empirical Bayes Approach to Estimating Ordinal Treatment Effects

Published online by Cambridge University Press:  04 January 2017

R. Michael Alvarez*
Affiliation:
California Institute of Technology, DHSS 228-77, 1200 E. California Blvd., Pasadena, CA 91125
Delia Bailey
Affiliation:
YouGov Polimetrix, 285 Hamilton Ave., Suite 200, Palo Alto, CA 94301
Jonathan N. Katz
Affiliation:
California Institute of Technology, DHSS 228-77, 1200 E. California Blvd., Pasadena, CA 91125
*
e-mail: [email protected] (corresponding author)

Abstract

Ordinal variables—categorical variables with a defined order to the categories, but without equal spacing between them—are frequently used in social science applications. Although a good deal of research exists on the proper modeling of ordinal response variables, there is not a clear directive as to how to model ordinal treatment variables. The usual approaches found in the literature for using ordinal treatment variables are either to use fully unconstrained, though additive, ordinal group indicators or to use a numeric predictor constrained to be continuous. Generalized additive models are a useful exception to these assumptions. In contrast to the generalized additive modeling approach, we propose the use of a Bayesian shrinkage estimator to model ordinal treatment variables. The estimator we discuss in this paper allows the model to contain both individual group—level indicators and a continuous predictor. In contrast to traditionally used shrinkage models that pull the data toward a common mean, we use a linear model as the basis. Thus, each individual effect can be arbitrary, but the model “shrinks” the estimates toward a linear ordinal framework according to the data. We demonstrate the estimator on two political science examples: the impact of voter identification requirements on turnout and the impact of the frequency of religious service attendance on the liberality of abortion attitudes.

Type
Research Article
Copyright
Copyright © The Author 2010. Published by Oxford University Press on behalf of the Society for Political Methodology 

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Footnotes

Authors' note: The views expressed here are those of the authors, not of any organizations they are currently or formerly associated with.

Editors' note: This article was accepted by the previous editorial team in consultation with the officers of the Society for Political Methodology. Unforeseen delays resulted in it appearing in an issue edited by two of the authors. These two authors played no editorial role for this article.

References

Agresti, Alan. 1990. Categorical data analysis. New York: Wiley-Interscience.Google Scholar
Aitchison, J., and Silvey, S. D. 1957. The generalization of probit analysis to the case of multiple responses. Biometrika 44: 131–40.Google Scholar
Aldrich, J., and Cnudde, C. F. 1975. Probing the bounds of conventional wisdom: A comparison of regression, probit, and discriminant analysis. American Journal of Political Science 19: 571608.Google Scholar
Alvarez, R. Michael, Bailey, Delia, and Katz, Jonathan N. 2007. The effect of voter identification laws on turnout. Unpublished Manuscript, California Institute of Technology and Washington University in St. Louis.Google Scholar
Alvarez, R. Michael, Hall, Thad E., and Sinclair, Betsy. 2008. Katrina's voters: Floods, representation, and social context Paper presented at the 2008 Annual Meetings of the Midwest Political Science Association.Google Scholar
Atkeson, Lonna Rae, Bryant, Lisa A., Hall, Thad E., Saunders, Kyle L., and Michael Alvarez, R. 2007. New barriers to participation: Application of New Mexico's voter identification law. Paper presented at the 2007 Annual Meeting of the American Political Science Association, Chicago, IL.Google Scholar
Barreto, Matt A., Nuno, Stephen A., and Sanchez, Gabriel R. 2007. Voter ID requirements and the disenfranchisement of Latino, Black and Asian voters. Paper presented at the 2007 Annual Meeting of the American Political Science Association, Chicago, IL.Google Scholar
Bates, Douglas. 2007. lme4: Linear Mixed-Effects Models Using S4 Classes. R package version 0.99875-9.Google Scholar
Beck, Nathaniel, and Jackman, Simon. 1998. Beyond linearity by default: Generalized additive models. American Journal of Political Science 42: 596627.Google Scholar
Combs, Michael W., and Welch, Susan. 1982. Blacks, white, and attitudes toward abortion. Public Opinion Quarterly 46: 510–20.Google Scholar
Gelman, Andrew, and Hill, Jennifer. 2006. Data Analysis Using Regression and Multilevel/Hierarchical Models. New York: Cambridge University Press.Google Scholar
Jones, Bradford S., and Westerland, Chad. 2006. Order matters(?): Alternatives to conventional practices for ordinal categorical variables. Paper presented at the Annual Meeting of the Midwest Political Science Association. Chicago, IL.Google Scholar
Kedar, Orit, and Phillips Shively, W. 2005. Introduction to the special issue. Political Analysis 13: 297300.Google Scholar
Lott, John R. 2006. Evidence of Voter Fraud and the Impact that Regulations to Reduce Fraud Have on Voter Participation Rates. http://ssrn.com/abstract=925611.Google Scholar
Maddala, G. S. 1983. Limited-Dependent and Qualitative Variables in Econometrics. Cambridge: Cambridge University Press.Google Scholar
McKelvey, R. D., and Zavonia, W. 1975. A statistical model for the analysis of ordinal level dependent variables. Journal of Mathematical Sociology 4: 103–20.Google Scholar
Miller, Warren E. 1991. Party identification, realignment, and party voting: Back to the basics. American Political Science Review 85: 557–68.Google Scholar
Mycoff, Jason D., Wagner, Michael, and Wilson, David. 2007. The effect of voter identification laws on turnout. Paper presented at the 2007 Annual Meeting of the American Political Science Association.Google Scholar
Nagler, Jonathan. 1991. The effect of voter registration laws and education on U.S. voter turnout. American Political Science Review 85: 1393–405.Google Scholar
R Development Core Team. 2007. R: A Language and Environment for Statistical Computing, version 26.1. Vienna, Austria: R Foundation for Statisical Computing. http://www.R-project.org.Google Scholar
Raudenbush, Stephen W., and Bryk, Anthony S. 2002. Hierarchical Linear Models: Applications and Data Analysis Methods. 2nd ed. Newbury Park, CA: Sage.Google Scholar
Rosenstone, S. J., and Wolfinger, R. E. 1978. The effect of registration laws on voter turnout. American Political Science Review 72: 2245.CrossRefGoogle Scholar
Singh, B. Kirshna, and Leahy, Peter J. 1978. Contextual and ideological dimensions of attitudes toward discretionary abortion. Demography 15: 381–88.CrossRefGoogle ScholarPubMed
Steenbergen, Marco R., and Jones, Bradford S. 2002. Modeling multilevel data structures. American Journal of Political Science 46: 218–37.Google Scholar
Tedrow, Lucky M., and Mahoney, E. R. 1979. Trends in attitudes toward abortion: 1972-1976. Public Opinion Quarterly 43: 181–89.Google Scholar
Vercellotti, Timothy, and Anderson, David. 2006. Protecting the franchise, or restricting it? The effects of voter identification requirements on turnout. Unpublished Manuscript, Rutgers University.Google Scholar
Western, Bruce. 1998. Causal heterogeneity in comparative research: A Bayesian hierarchical modeling approach. American Journal of Political Science 42: 1233–59.Google Scholar