Projection effects and specification bias in spatial models of European Parliament elections

Substantial empirical evidence suggests that voters cast their ballot not only by considering the different policy positions of parties or candidates, but also appear to pull candidates/parties they prefer closer to their own ideal position (‘assimilation’) while pushing candidates/parties they dislike, farther away (‘contrast’). These effects are called ‘projection effects’. We illustrate that voters’ perceptions of policy positions of candidates/parties are contaminated by non-spatial considerations. Building on data from the EES series, we empirically demonstrate that projection effects are substantively meaningful and statistically significant in elections to the European Parliament. We moreover distinguish between unsystematic projection bias that only depends on the closeness to a specific candidate or party and systematic projection bias that is also affected by party-, voter-, and context-specific determinants.