The article explains the incumbency advantage by examining how incumbents signal their ideological positions differently than challengers. It uses voter-level data from the Cooperative Congressional Election Study and accounts for unobserved district heterogeneity.
📊 Voter Perception Mechanisms:
- Incumbents rely on individual candidate ideology to establish party alignment
- Challengers are primarily identified through party affiliation in House races, but less so in Senate contests
🔍 Signaling Decomposition:
The study breaks incumbency advantage into components. Results show:
- Ideological signaling accounts for 14% of the advantage in US House elections
- This mechanism explains only 5% of the advantage in Senate races
⚖️ Policy Implications:
A 50% increase in party polarization boosts the incumbency gap by approximately 3 percentage points.
