ON THE (MIS)MEASUREMENT OF LEGISLATOR IDEOLOGY AND SHIRKING

In this paper, we show that current statistical measures of legislator 's shirking are implicitly based on the electoral concept of a unique majority rule equilibrium point in the policy space where elections ar e contested. We note that such equilibria do not exist generically and present statistical results showing that cross-sectional regressions where legislators' voting indices are predicted by district average de mograhic and economic data are mis-specified. We also discuss a weaker equilibrium construct, the uncovered set, and present statistical evi dence showing that differences in voting behavior between Senators fro m the same state are positively related to the heterogeneity of the el ectorate. We argue that current evidence alleged to show shirking by S enators is equally consistent with Senators who perfectly represent an idiosyncratic constituency that cannot be represented by district ave rage data.