Nielson Brothers Polling
Historical accuracy is measured against certified results. Current-cycle records come from the canonical, deduplicated archive and do not by themselves change the sealed forecast.
- Historical polls
- 11
- Mean absolute error
- 12.26percentage points
- Historical bias
- D+5.86
- Represented cycles
- 42010–2020
- Current archive
- 0canonical records
- History span
- Oct 21, 2010through Oct 26, 2020
Known names and relationships
- Known aliases
- No additional reviewed aliases
- Organization type
- Single canonical organization
- Cycles represented
- 2010 · 2012 · 2016 · 2020
11 eligible historical polls across 4 represented cycles passed the published history identity checks. Historical bias is descriptive and is kept separate from sponsor or client affiliation.
Current-cycle records
Archive source date 2026-09-09 · bundled copy. Archive records may be newer than the sealed forecast; inclusion here does not mean the forecast uses them.
0 shown · 0 total
No record in the currently authorized canonical archive is attached to this identity.
This is not evidence that the pollster released no 2026 polling; the source-audit gaps remain documented.
Eligible historical observations
11 shown · 11 total
| Cycle | Race | Type | Field end | Sample | Poll | Result | Error |
|---|---|---|---|---|---|---|---|
| 2020 | 2020_Sen-G_SD | Sen-G | 2020-10-26 | 479 | R+17.0 | R+31.5 | D+14.5 |
| 2020 | 2020_Pres-G_SD | Pres-G | 2020-10-26 | 484 | R+15.0 | R+26.2 | D+11.2 |
| 2016 | 2016_Sen-G_SD | Sen-G | 2016-10-25 | 600 | R+19.0 | R+43.7 | D+24.7 |
| 2016 | 2016_Pres-G_SD | Pres-G | 2016-10-25 | 600 | R+14.0 | R+29.8 | D+15.8 |
| 2016 | 2016_House-G_SD-1 | House-G | 2016-10-25 | 600 | R+10.0 | R+28.2 | D+18.2 |
| 2012 | 2012_Pres-G_SD | Pres-G | 2012-11-02 | 633 | R+12.0 | R+18.0 | D+6.0 |
| 2012 | 2012_House-G_SD-1 | House-G | 2012-11-02 | 612 | R+13.0 | R+14.9 | D+1.9 |
| 2012 | 2012_Pres-G_SD | Pres-G | 2012-10-30 | 671 | R+8.0 | R+18.0 | D+10.0 |
| 2012 | 2012_House-G_SD-1 | House-G | 2012-10-30 | 771 | R+6.0 | R+14.9 | D+8.9 |
| 2010 | 2010_House-G_SD-1 | House-G | 2010-10-21 | 679 | D+1.5 | R+2.2 | D+3.7 |
| 2010 | 2010_Gov-G_SD | Gov-G | 2010-10-21 | 679 | R+3.0 | R+23.0 | D+20.0 |
Method · historical final-three-week D/R general-election rows plus verified historical supplement; min n=5
Definition · bias_D is poll D-R margin minus actual D-R margin; positive overstates Democrats.
A missing sample, sponsor or source is labeled unavailable; it is never reconstructed.
Poll data via VoteHub, used under CC BY 4.0. Poll data from The New York Times, used under CC BY 4.0.