On September 10, 2012, immediately following the close of the Democratic Party's national nominating convention and 57 days before Election Day on November 6, my Convention Bump and Economy Model predicted that Barack Obama was likely to receive 51.3% of the national two-party popular vote. The Convention Bump and Economy Model consists of Gallup's preconvention preference poll, the net convention bump in the polls, and an adjusted second quarter GDP growth rate. The forecast pegged the certainty of an Obama plurality at 67%. No sure thing, but more likely than not. The traditional Trial-Heat and Economy Model predicted Obama's vote at 52.0%. The Convention Bump and Economy Model's prediction was the preferred forecast in 2012 because of the lateness of the parties' nominating conventions. Democrats did not even begin their convention until after Labor Day.

President Obama's actual share of the two-party vote was 51.8 percentage points. The Convention Bump and Economy Model's forecast error was a mere half of a percentage point. This is about as accurate as it gets. Of course, some portion of the forecast's accuracy is the result of an omitted variable: luck. No mix of the fundamentals can be reasonably expected to produce a forecast with anything approaching this accuracy, and there were at least the normal number of unanticipated twists and turns in this campaign that could not possibly have been predicted. Among these were the release of the “47 percent” video of Romney that offended some voters, President Obama's poor performance in the first debate, the odd handling by all involved (including the third debate's moderator) of the issue regarding the administration's response to the terrorist attack in Libya and, perhaps most notably, President Obama's response to Hurricane Sandy about a week before the election accompanied by New Jersey's Republican governor Chris Christie's effusive praise for the president. There were certainly many other events as well. Beyond the public arena, the forecast also would not take into account in any way the superior “get out the vote” efforts of the Obama campaign.

Although many important events and developments took place during this campaign that the forecast could not have anticipated, many of these offset one another. The “47 percent video” and hurricane events helped President Obama, but the first debate helped Governor Romney. But beyond the simple cancelling effects of campaign events, this campaign sheds some light on the interesting interactions of the fundamentals and unanticipated campaign events. The pro-Romney effect of the first debate was a mix of the contrast between Romney's masterful and Obama's sleepwalking performance, but also President Obama's weak economic record—a fundamental context of the election. Obama's weak economic record was the ammunition for Romney's strong debate showing and would not have been possible without it. The pro-Obama effect of Hurricane Sandy could not have been anticipated because the hurricane itself could not have been anticipated, but when it happened it reflected the impact of presidential incumbency, another fundamental context undergirding the election forecast.

In reviewing the Convention Bump and Economy forecast of the 2012 election, the forecast model appears to have captured successfully the precampaign fundamentals that largely shape presidential elections. The 2012 experience is only one election, but it should reinforce confidence in the model.

One final note: Democratic Party seat gains in the House of seven or eight seats were almost perfectly predicted between the Seats-in-Trouble Model's forecasts for Democrats to pick up between three and 14 seats.