This article introduces State Legislative Effectiveness Scores (SLES) for state legislators across 97 legislative chambers over recent decades, measuring who actually advances public policy in the American states.

📊 How the Scores Were Constructed

• Scores combine three concrete elements: the number of bills a legislator sponsors, how far those bills progress through the lawmaking process, and the substantive importance of those bills.
• Coverage spans 97 state legislative chambers across recent decades, producing comparable measures of individual lawmakers' policy impact.

📈 How the Scores Were Tested

• The SLES are assessed through both criterion and construct validation to establish reliability and meaning.
• Validation demonstrates that the scores capture legitimate variation in legislative effectiveness and help distinguish more from less effective lawmaking behavior.

🔎 Two Illustrations Showing What SLES Can Do

• Party Power: Greater majority-party influence over lawmaking is evident in states that feature ideological polarization and majority-party cohesion, and in states with higher electoral competition for chamber control.
• Institutional Design: Choices such as legislative rules and the scope of professionalization shape how policymaking power is distributed across legislators from state to state.

💡 Why This Matters

• These scores reveal new insights into effective lawmaking across individual legislators and open immense opportunities for new scholarship on legislative behavior, party influence, and institutional effects in state politics.