Market Shares Corp.
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
- 22
- Mean absolute error
- 6.05percentage points
- Historical bias
- R+2.65
- Represented cycles
- 81998–2012
- Current archive
- 0canonical records
- History span
- Oct 19, 1998through Oct 22, 2012
Known names and relationships
- Known aliases
- No additional reviewed aliases
- Organization type
- Single canonical organization
- Cycles represented
- 1998 · 2000 · 2002 · 2004 · 2006 · 2008 · 2010 · 2012
22 eligible historical polls across 8 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
22 shown · 22 total
| Cycle | Race | Type | Field end | Sample | Poll | Result | Error |
|---|---|---|---|---|---|---|---|
| 2012 | 2012_House-G_IL-8 | House-G | 2012-10-22 | 600 | D+10.0 | D+9.5 | D+0.5 |
| 2010 | 2010_Sen-G_IL | Sen-G | 2010-10-20 | 700 | R+3.0 | R+1.6 | R+1.4 |
| 2010 | 2010_Gov-G_IL | Gov-G | 2010-10-20 | 700 | R+4.0 | D+0.8 | R+4.8 |
| 2008 | 2008_Pres-G_IL | Pres-G | 2008-10-17 | 500 | D+24.0 | D+25.1 | R+1.1 |
| 2006 | 2006_Gov-G_IL | Gov-G | 2006-10-28 | 600 | D+15.0 | D+10.5 | D+4.5 |
| 2004 | 2004_Sen-G_IL | Sen-G | 2004-10-18 | 700 | D+47.0 | D+43.0 | D+4.0 |
| 2004 | 2004_Pres-G_IL | Pres-G | 2004-10-18 | 700 | D+8.0 | D+10.3 | R+2.3 |
| 2002 | 2002_House-G_IN-7 | House-G | 2002-10-30 | 400 | D+1.0 | D+9.0 | R+8.0 |
| 2002 | 2002_Sen-G_IL | Sen-G | 2002-10-26 | 701 | D+20.0 | D+22.3 | R+2.3 |
| 2002 | 2002_Gov-G_WI | Gov-G | 2002-10-26 | 450 | D+2.0 | D+3.7 | R+1.7 |
| 2002 | 2002_Gov-G_IL | Gov-G | 2002-10-26 | 701 | D+10.0 | D+7.1 | D+2.9 |
| 2000 | 2000_Pres-G_WI | Pres-G | 2000-11-05 | 400 | R+5.0 | D+0.2 | R+5.2 |
| 2000 | 2000_Sen-G_WI | Sen-G | 2000-10-27 | 500 | D+33.0 | D+24.5 | D+8.5 |
| 2000 | 2000_Sen-G_IN | Sen-G | 2000-10-27 | 600 | R+59.0 | R+34.7 | R+24.3 |
| 2000 | 2000_Pres-G_WI | Pres-G | 2000-10-27 | 500 | R+7.0 | D+0.2 | R+7.2 |
| 2000 | 2000_Pres-G_IN | Pres-G | 2000-10-27 | 600 | R+23.0 | R+15.6 | R+7.4 |
| 2000 | 2000_Gov-G_IN | Gov-G | 2000-10-27 | 600 | D+16.0 | D+14.9 | D+1.1 |
| 2000 | 2000_Pres-G_IL | Pres-G | 2000-10-22 | 899 | D+10.0 | D+12.0 | R+2.0 |
| 1998 | 1998_Sen-G_WI | Sen-G | 1998-10-23 | 600 | R+3.0 | D+2.1 | R+5.2 |
| 1998 | 1998_Gov-G_WI | Gov-G | 1998-10-23 | 600 | R+41.0 | R+21.0 | R+20.0 |
| 1998 | 1998_Sen-G_IL | Sen-G | 1998-10-19 | 1,099 | R+10.0 | R+2.9 | R+7.1 |
| 1998 | 1998_Gov-G_IL | Gov-G | 1998-10-19 | 1,099 | R+15.0 | R+3.6 | R+11.4 |
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.