🔍 Key Question and Surprise Finding:

Compulsory voting is typically thought to close the turnout gap between rich and poor. Using Brazil—the largest country that enforces compulsory voting—evidence shows the opposite: compulsory voting increases turnout inequality by education (a proxy for socioeconomic status).

📊 Massive Voter Records and Age Cutoffs:

• Individual-level administrative data covering 140 million Brazilian citizens were analyzed.
• Two age-based discontinuities provide quasi-experimental leverage to estimate causal, heterogeneous effects by educational attainment.
• Educational achievement is used as a strong proxy for socioeconomic status.

📈 What Was Found:

• Across both age thresholds, the causal effect of compulsory voting on turnout is at least twice as large for the more educated than for the less educated.
• Rather than narrowing participation differences, compulsory voting increases turnout inequality in Brazil.

🧭 Evidence for Why This Happens:

• Nonmonetary penalties for abstention (for example, administrative costs or reputational effects) disproportionately influence middle- and upper-class voters, driving larger turnout increases in those groups.
• Survey evidence from a national sample supports this mechanism linking nonmonetary sanctions to differential turnout responses.

💡 Why It Matters:

These results run counter to standard expectations about compulsory voting and suggest that the design and enforcement of nonmonetary sanctions can reverse predicted redistributive effects. Studies and policymakers should account for how nonmonetary penalties shape who responds to compulsory voting rules.