The incumbency effects of signalling

Much literature on political behaviour treats politicians as motivated by re-election, choosing actions to signal their types to voters. We identify a novel implication of incumbent signalling. Because incumbents only care about clearing a re-election hurdle, signals will tend to cluster just above the threshold needed for re-election. This generates a skew distribution of signals leading to an incumbency advantage in the probability of election. We also solve for the optimal threshold when voters have the ability to commit.