Published online by Cambridge University Press: 25 January 2021
I present a measure of legislative professionalism for 41 states based on the degree to which legislators hold outside careers while in office. Higher salaries and longer sessions alter the incentives and opportunities for legislators to maintain outside careers. Consequently, outside career activity provides a behavioral indicator of professionalism to supplement existing measures based solely on institutional characteristics. I use financial disclosure reports to assess outside interests. Aggregated to the state level, my indicator is highly correlated with institutional measures of professionalism; at the individual level, it varies by sex and age. These findings support hypotheses that outside career choices are influenced by labor market participation and the financial opportunity costs of legislative service.