The Source of the Legislative Professionalism Advantage: Attracting More Knowledgeable Candidates

Legislators who know their constituents’ opinions are more likely to be successful in providing substantive representation on issues of the day. However, previous work suggests that state legislators and candidates commonly misestimate their constituents’ preferences. Some of that work also finds that candidates and current incumbents in highly professionalized legislatures are less likely to misestimate constituent opinion. We investigate why this professionalism advantage exists. We use a Blinder–Oaxaca decomposition to determine how much of the professionalism advantage can be attributed to three sources: attracting knowledgeable candidates, fostering legislator knowledge in office, and retaining incumbents. We apply the decomposition to data on candidates’ perceptions of public opinion from the 2014 National Candidate Survey. Fostering knowledge in office and retaining incumbents are not responsible for the professionalism advantage. We find evidence that the professionalism advantage occurs because higher professionalism legislatures attract more knowledgeable nonincumbent candidates.