Siena College
Graded against the actual result across 75 races (from 138 polls, through 2024).
Head-to-head vs VotePredictor Elections
The fair, apples-to-apples test: on the 74 races Siena College actually polled, how its final poll's margin compared to what VotePredictor Elections predicted for those same races.
| Model | Avg miss (pts) | Called right |
|---|---|---|
| Siena College | 5.10 | 85% |
| VotePredictor Elections | 5.46 | 85% |
VotePredictor Elections aggregates all the pollsters, so it's expected to beat any single one on margin — that's the value of averaging. The honest comparison among forecasters is on the combined board.
Every race (75)
Each race Siena College polled, scored on its final poll — the call right before the vote — against the actual Dem−Rep result. Click a race for its full detail.
Accuracy by time to election
Lower is better. Time to election runs right (election week) to left (~2 months out).
By the numbers
| Time to election | Polls | Avg miss | vs field | Called right |
|---|---|---|---|---|
| ≤1 wk | 14 | 4.94 | +0.70 | 93% |
| 1–3 wk | 39 | 5.04 | -0.02 | 87% |
| 3–6 wk | 51 | 7.56 | +1.86 | 73% |
| 6–9 wk | 34 | 8.79 | +2.65 | 77% |
vs field is this pollster's average miss minus all pollsters' at the same lead time — green beats the field, redtrails it. Our historical polls reach ~2 months out; earlier polling isn't in the record.
Track record by cycle — getting better?
| Year | Polls | Avg miss | Lean (house effect) |
|---|---|---|---|
| 2006 | 8 | 8.0 | R+0.8 |
| 2008 | 3 | 10.2 | R+7.2 |
| 2009 | 7 | 21.1 | R+20.1 |
| 2010 | 18 | 6.6 | D+5.5 |
| 2011 | 4 | 5.7 | R+0.1 |
| 2012 | 21 | 5.5 | R+4.4 |
| 2014 | 16 | 8.8 | D+8.0 |
| 2016 | 16 | 3.0 | D+0.8 |
| 2018 | 9 | 4.8 | R+4.8 |
| 2020 | 4 | 10.1 | D+10.1 |
| 2022 | 23 | 5.8 | D+5.2 |
| 2024 | 5 | 6.9 | D+5.2 |
Do we credit a pollster for fixing its bias? Each cycle, the model re-estimates every pollster's lean from all its earlier polls (walk-forward) and subtracts it before using the poll. We tested weighting recent cycles more — it doesn't help: a pollster's lean in one cycle barely predicts the next (correlation 0.28), so the swings above are mostly noise, and averaging over more history beats chasing the latest cycle. The all-time estimate we use came out within ~0.5% of the best option.