Search Results Use the search box below to revise your search, or start a new search. Studies (2) Variables Publications Your query returned 2 studies. Series results are grouped under the most relevant study. Ungroup series results to view all results. Sort by: Study Relevance Title A-Z Released/Updated Time Period Most Cited in ICPSR Bib. Variable Relevance 1. Comparative Study of Electoral Systems, 1996-2001 (ICPSR 2683) Sapiro, Virginia; Shively, W. Philips 2. Global Digital Activism Data Set, 2013 (ICPSR 34625) Joyce, Mary; Rosas, António; Howard, Philip N.