📚 Evidence Reviewed

A meta-analytical review synthesizes over 1,000 empirical estimates from 71 studies conducted across three decades to assess how the distribution of executive power relates to corruption in democracies.

🔎 How the Review Was Conducted

The literature was aggregated using a formal meta-analytical framework that pooled effect estimates across studies. Moderator analyses examined how research-design choices influence conclusions, with explicit attention to:

• temporal coverage of study samples
• spatial (cross-national or within-country) coverage
• selection of control variables (co-parameters) in statistical tests

📈 Key Findings

• Presidentialism shows a consistent positive association with corruption across the pooled evidence.
• Decentralization effects depend on type: political decentralization has a marginal positive association with corruption, whereas fiscal decentralization has a negative association (linked to lower corruption).
• Several results are sensitive to study design choices; in particular, temporal and spatial sample coverage and which co-parameters are included often alter estimates and their interpretation.

⚖️ Why It Matters

The review helps reconcile conflicting findings in the literature by distinguishing fiscal from political decentralization and by highlighting systematic differences between presidential and parliamentary systems. These nuances matter for scholars interpreting empirical results and for policymakers considering institutional reforms or anti-corruption interventions, because conclusions can hinge on measurement choices and sample coverage.