Incumbent parties, incumbent MPs and the effectiveness of constituency campaigns: evidence from the 2015 UK general election

Parties’ local campaign efforts can yield electoral dividends in plurality elections; in general, the harder they campaign, the more votes they receive. However, this is not invariably the case. Different parties’ campaigns can have different effects. What is more, the particular status of a candidacy can also influence how effective the local campaign might be. Analyses of constituency campaigning at the 2015 UK General Election reveal inter-party variations in campaign effectiveness. But looking more closely at how a party was placed tactically in a seat prior to the election, and at whether sitting MPs stood again for their party or retired, reveals distinct variations in what parties stand to gain from their local campaigns in different circumstances.