Princeton Election Consortium

A first draft of electoral history. Since 2004

Meta-Margins for control: House D+1.0% Senate R+4.2% Find key elections near you!

2004 State-by-State Probabilities

Current percentage probabilities of a Kerry win in each battleground state, computed from the last three polls or going back seven days, whichever gives more polls. States in boldface had a new poll completed and released since the last day of updates. The probabilities are calculated assuming that the SEM cannot go below 2%. Click on a state to view a tabulation of most of the polls. Some of the others come from these data sources (some are subscription-only). Other sources are and RealClearPolitics. All data are visible in this MATLAB script.

This is a history of the calculation. For this calculation each poll is assigned to the last date on which polling was done. The marked events are inspired by a similar graph by In my graph, the effect of events is clearer because I use polling margins and because I average over three polls. Fahrenheit 9/11, adding John Edwards to the ticket, and the Democratic convention seemed to have measurable effects within a few days. The passing of Ronald Reagan and the assault on Kerry’s war heroism did not. The last update was October 12. Note: Around the time of the first debate I started using more polls per state. This and the start of Rasmussen daily tracking polls has complicated updates. Therefore after September 25 the graph is simply a record of previous daily updates – not quite the same. For instance, in this graph the bounce from the first debate looks delayed. In fact, it was immediate. This graph will be done more properly soon.

History of meta-analysis over time