The theoretical public-choice literature suggests that vote trading is an important determinant of congressional voting behavior. Yet empirical voting models do not allow for vote trading. These models recognize that observed ideology may influence legislative behavior but do not correct for unobserved ideology. This study devises new tests for logrolling and ideology. The empirical model controls for logroll agreements and unobserved ideological interest via the correlation of unobserved variables. The results reflect the presence of vote-trading coalitions on some votes but not on others. The results cast doubt on the importance of personal ideological interests of legislators.

The theoretical public-choice literature suggests that vote trading is an important determinant of congressional voting behavior. Yet empirical voting models do not allow for vote trading. These models recognize that observed ideology may influence legislative behavior but do not correct for unobserved ideology. This study devises new tests for logrolling and ideology. The empirical model controls for logroll agreements and unobserved ideological interest via the correlation of unobserved variables. The results reflect the presence of vote-trading coalitions on some votes but not on others. The results cast doubt on the importance of personal ideological interests of legislators. Copyright 1992 by American Economic Association.

Empirical public choice literature and casual observation suggest that the behavior of political action committees is remarkably unsophisticated, meaning that PACs give to those legislators who would support their interests anyway. Thus it is suggested that contributor behavior deviates from rational behavior, which is a cornerstone of economic analysis. In this paper, a switching regression model is estimated that allows for strategies of PACs to vary for different contribution recipients. I analyze the behavior of farm PACs over three election cycles. In contrast to previous findings, I find that contributor behavior is not inconsistent with rational behavior. Contributors who attempt to influence the voting behavior of members of Congress give the most money to legislators whose constituency interest suggests that they are likely to be undecided on how to vote and PACs give less money to legislators who represent districts with larger farm populations because those legislators are likely to vote in contributor interests anyway.

Empirical public choice literature and casual observation suggest that the behavior of political action committees is remarkably unsophisticated, meaning that PACs give to those legislators who would support their interests anyway. Thus it is suggested that contributor behavior deviates from rational behavior, which is a cornerstone of economic analysis. In this paper, a switching regression model is estimated that allows for strategies of PACs to vary for different contribution recipients. I analyze the behavior of farm PACs over three election cycles. In contrast to previous findings, I find that contributor behavior is not inconsistent with rational behavior. Contributors who attempt to influence the voting behavior of members of Congress give the most money to legislators whose constituency interest suggests that they are likely to be undecided on how to vote and PACs give less money to legislators who represent districts with larger farm populations because those legislators are likely to vote in contributor interests anyway.