Wednesday, May 21, 2008

Forecasting Update

With almost all of the votes (95%) counted in Oregon it is pretty clear that the yesterday's outcomes did not deviate much from what was expected based on pre-primary polling data. The table below summarizes the accuracy of my pre-primary forecasts, which were based on the polling trends at

Clinton Percent of the Two-Candidate Vote

Forecast Vote

Actual Vote

Forecast- Actual




-.4 points




2.2 points

The model nailed the Kentucky outcome and over-predicted Clinton's Oregon vote by 2.2 percentage points.

Monday, May 19, 2008

KY and OR Forecasts

I've got jury duty in the morning so I'm posting my Kentucky and Oregon forecasts now based on the 5/19 poll trend summary from . These forecasts are based on estimates generated from the same forecasting model used before, but updated to include data from North Carolina and Indiana.

The projected percent of the the two-candidate vote going to Clinton is:

Kentucky 68.2%

Oregon 43.5%

The model missed Indiana and North Carolina by 2.1 and 4.0 points, respectively, so it will be interesting to see how it does tomorrow.

Tuesday, May 6, 2008

Indiana and North Carolina Forecasts

Forecast of Clinton vote: 52.7% in Indiana and 46.7% in North Carolina.

Details of Model:

To reiterate, the the model is based on the relationship between Charles Franklin's final, pre-election estimates of poll standing (in states where there were enough polls to generate estimates, and excluding Florida) and actual votes cast. I also include a control variable for whether the final poll figure included an estimate for John Edwards' share of the vote.

I've updated the model to include data from the Pennsylvania primary, which has since occurred, as was well as from Wisconsin, which was inexplicably and inadvertently excluded from the earlier estimates.

The new estimates, which are very similar to those originally reported, are presented below.








Edwards (0,1)









R-squared =.85

Franklin's estimates of Clinton's percent of the two-party vote (as of 11:45 a.m. CST in this case) are 52.26 % in Indiana and 46.03% in North Carolina. Plugging those numbers into the model produces the forecasts of 52.7% and 46.7% of the vote for Clinton in Indiana and North Carolina, respectively.