Funded by grants from the National Science Foundation, these studies have involved extensive surveys of major party activists in every presidential election from 1980 through 1996. The questions motivating the study relate to participation and candidate choice in presidential nomination campaigns, and the impact of participation in the nomination phase on involvement in the general election stage. The surveys of caucus attenders and convention delegates in the Democratic and Republican Parties include items on campaign activity, issue opinion, perceptions of the candidates and parties, participation in interest groups, and demographics. In most years, we have cross-section surveys of party activists, and all years are linked by various panels which span from four to sixteen years.