The convention bump

Do the national conventions of the Democratic and Republican parties affect the poll standings of the presidential candidates they nominate? This study investigates whether these poll stand ings are bumped upwards following the party conventions. The convention bump is examined with Gallup and Harris time series data of presidential trial-heats throughout the course of seven campaigns from 1964 to 1988. We find that (1) with few exceptions, there is a convention bump; (2) the bump typically adds about 5 to 7 percentage points to the nominee's postoonvention poll standing; (3) the effects of conventions carry well into the general election campaign; (4) the first convention in the campaign sequence, held by the out-party, generates an additional but temporary increase in the nominee's support; and (5) convention bumps may be greater for harmonious conventions following divisive nomination contests.