*************************************** Research Workshop in Applied Statistics *************************************** Please join us this Wednesday @ noon at CBRSS, the Center for Basic Research in the Social Sciences, 34 Kirkland Street, Rm 22, for a presentation by Elizabeth Stuart. Her talk is titled "Matching with Multiple Control Groups". *ABSTRACT* In observational studies, it is desirable to reduce bias due to covariates by obtaining treated and control groups with similar distributions of the covariates. This is often done by choosing well-matched samples of the original treated and control groups. However, sometimes the originally chosen control units cannot provide adequate matches for the treated units. In these cases, it may be desirable to obtain matched controls from two control groups. Multiple control groups have been used in the context of causal inference to test for hidden biases; however, little work has been done on their use in matching or adjustment for these biases. We provide a theoretical basis and practical guidelines for this new approach. The motivating example is a school- wide dropout prevention program where students in the original treated and control schools were significantly different from one another. We consider the use of a second source of control students to supplement the original group. As always, lunch will be provided. Contact information, the current schedule, and previous presentations may be found at the course web site: http://www.courses.fas.harvard.edu/~gov3009/ ****************************************** The Research Workshop in Applied Statistics is a forum for graduate students, faculty, and visiting scholars to present and discuss work in progress and exchange ideas. It is intended as a tour of Harvard's statistical innovations and applications with weekly stops in different disciplines such as economics, epidemiology, medicine, political science, psychology, public policy, public health, sociology and statistics. The topics of papers presented in previous years included missing data, survey analysis, Bayesian simulation, sample selection, and models for election and portfolio choice. Faculty and student participants in the workshop present their current projects, and guest speakers also give occasional presentations. The workshop provides an excellent opportunity for informal interaction between graduate students and faculty from a variety of disciplines. Course credit is available for students as either an upper-level Government or Sociology class. Lunch is provided. If you are interested, note that all events are held at noon, in Room 22, Center for Basic Research in Social Sciences (CBRSS, 34 Kirkland St., this is the yellow building across the street from William James Hall). Contact information and previous presentations may be found at the course web site: http://www.courses.fas.harvard.edu/~gov3009/ To join the gov3009 mailing list, send e-mail to gov3009-l-request(a)fas.harvard.edu with the following text message: subscribe end