Here are final polling snapshots for gubernatorial races that are either close or likely to switch party control:
Put your own predictions in comments! Some more notes…
The calculations above are a benchmark for how well we can do with polls alone. No house-effects corrections or fundamentals-based modeling was done.
Technical notes: For each state, at least three polls were used. The number of polls was determined using the variance-minimization method. All data were taken from HuffPollster. The median (no more than one poll per pollster) and the estimated SEM are shown in the second column. The win probability was calculated assuming an additional possible 2.0% error in the home stretch to account for polling error or bias. This was converted to a probability using the t-distribution (3 d.f.). To see how many polls were used, see this spreadsheet.
I’ll incorporate this into the 2014 Geek’s Guide, hopefully by midday Tuesday. In the meantime, please give your own predictions in comments. What surprises do you predict?