We investigate two age-old questions of interest group behavior: how have interest
group coalition strategies changed over time; and which factors determine whether interest groups
work together? Through the creation of a new network measure of interest group coalitions based on
cosigner status to United States Supreme Court amicus curiae briefs, we illuminate the central players
and overall characteristics of this dynamic network from 1930 to present-day. We also model the
attribute homophily and structure of the network. We find assortative mixing of interest groups based
on policy area, region, size, and other business characteristics.
Janet M. Box-Steffensmeier (Ph.D., Texas, 1993), Vernal Riffe Professor of Political Science, pursues research and teaching interests in American politics (legislative politics, public opinion, and voting behavior) and in methodology (time series, event history, and network analysis). She has published articles in the American Political Science Review, American Journal of Political Science, Journal of Politics, Political Analysis, and Legislative Studies Quarterly. She is the author of Event History Modeling: A Guide for Social Scientists, published by Cambridge University Press. She is currently working on a Monte Carlo project to evaluate the treatment of heterogeneity in event history models, which is partially funded by the National Science Foundation. Other funded research includes projects on the use of Blue Slips by Senators to oppose court nominations. She has twice received the Gosnell Award for the best work in political methodology and the Emerging Scholar Award of the Elections, Public Opinion, and Voting Behavior Section of the American Political Science Association. She is the former treasurer of the American Political Science Association and President Elect of the Midwest Political Science Association.