Harris Insights & Analytics
Graded against the actual result across 127 races (from 241 polls, through 2024).
Head-to-head vs VotePredictor Elections
The fair, apples-to-apples test: on the 26 races Harris Insights & Analytics actually polled, how its final poll's margin compared to what VotePredictor Elections predicted for those same races.
| Model | Avg miss (pts) | Called right |
|---|---|---|
| Harris Insights & Analytics | 4.84 | 69% |
| VotePredictor Elections | 3.57 | 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 (126)
Each race Harris Insights & Analytics 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 | 123 | 4.41 | +0.17 | 81% |
| 1–3 wk | 56 | 6.78 | +1.72 | 79% |
| 3–6 wk | 10 | 3.04 | -2.66 | 90% |
| 6–9 wk | 52 | 5.43 | -0.71 | 87% |
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) |
|---|---|---|---|
| 1998 | 48 | 8.4 | R+5.5 |
| 2000 | 122 | 4.5 | D+1.1 |
| 2004 | 11 | 3.7 | D+1.4 |
| 2008 | 4 | 2.5 | R+2.1 |
| 2018 | 27 | 4.3 | D+0.1 |
| 2020 | 19 | 2.7 | D+2.6 |
| 2024 | 7 | 6.3 | R+4.1 |
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.