Do Candidates Matter? Constituency-specific Vote Changes for Incumbent MPs, 1983–1987

The assumption that candidates make a difference to electoral outcomes in British general elections is tested through a comparison of the 1983 and 1987 general elections. Incumbent's Constituency-specific Vote Change (ICVC) between the June 1983 and June 1987 British general elections is measured by subtracting the average regional vote change for the incumbent's party from the constituency vote change registered by the incumbent. Regression analysis finds ICVC to be most significantly influenced in both the Labour and Conservative parties by the incumbent's length of tenure, displayed especially in the higher ICVC registered by first-term incumbents than by more senior incumbents. Variables indicating the security or insecurity of the seat in electoral terms are significantly related to ICVC in the Conservative but not in the Labour case. The findings for Labour indicate ICVC to be greater where electoral security is greater. This finding might be explained by successful Conservative party concentration on constituencies in which Labour incumbents appear to be vulnerable.