Comparing Interest Group PAC Contributions to House and Senate Incumbents, 1980-1986

Most work on the allocation patterns of campaign contributions by interest groups focuses on the relative productivity of legislators' effort in serving each group. Short time-series and cross-sectional studies of PAC activity have been done for the House of Representatives and the Senate separately, but no study has used (1) longer time series data or (2) made explicit comparisons among interest group (corporations, unions, and trade associations) activities, considering (3) differences in the time series pattern of groups across the two chambers. We integrate all three perspectives here, using data covering the 1980-1986 election cycles. The results represent preliminary estimates of the dollar value to interest groups of the personal and institutional characteristics of legislators, where these characteristics are allowed for the first time to vary across chambers.