House Effects
Monday, September 21, 202643 days until Election Day, November 3, 2026
2000–2024

How this average would have done

The same averaging rules the site uses today, run on 2,300 past general elections, using only polls published by two days before each election and pollster information from earlier years. It is a backtest, not a record of calls made in real time. Before 2018 the poll archive covers only the final two months of each race. How the rules were chosen.

By cycle

Average miss of the final polling average

Mean absolute error on the margin, two days out. In parentheses: which way the polls missed on average that year.

CycleSenateGovernorHousePresident
20004.7 (R+2.1; 31)3.0 (R+0.4; 11)4.6 (D+1.0; 29)4.1 (R+0.6; 52)
20025.0 (D+1.4; 27)5.3 (D+3.3; 36)5.2 (D+1.2; 56)
20045.0 (D+2.6; 27)3.1 (D+1.7; 10)4.8 (D+0.8; 51)3.0 (D+0.9; 54)
20063.6 (R+2.7; 28)3.5 (even; 35)5.0 (R+0.3; 103)
20084.1 (R+0.5; 34)4.1 (D+0.5; 11)5.0 (D+0.2; 91)3.6 (R+1.0; 55)
20104.4 (R+0.6; 36)4.3 (D+1.0; 37)6.0 (D+1.1; 159)
20124.3 (R+3.8; 28)3.3 (R+2.8; 9)6.5 (R+4.4; 102)3.9 (R+1.4; 46)
20144.2 (D+3.1; 34)4.6 (D+3.7; 35)6.3 (D+3.6; 74)
20165.5 (D+4.5; 33)5.3 (D+3.7; 12)6.1 (D+3.2; 62)5.5 (D+3.7; 57)
20183.6 (R+0.1; 31)3.9 (R+0.7; 34)5.9 (R+0.9; 160)
20206.6 (D+6.4; 32)8.0 (D+8.0; 11)5.9 (D+4.8; 105)5.1 (D+4.5; 55)
20225.6 (D+2.6; 31)5.0 (D+2.9; 34)5.6 (R+0.2; 112)
20244.9 (D+4.2; 31)6.8 (D+6.7; 11)5.3 (D+2.8; 85)4.8 (D+4.2; 51)

House figures cover only districts that were polled. The last number in each cell is the count of races.

Race by race

Final averages against results

31 races · average miss 4.9 · winner called in 97%
RaceFinal averageResultMiss (toward)PollsPollstersWinner called
AZD+5.8D+2.4D+3.49540Yes
CAD+20.2D+17.7D+2.411Yes
CA (second contest that year)D+23.2D+17.7D+5.5187Yes
CTD+15.8D+18.9R+3.111Yes
DED+20.5D+17.1D+3.411Yes
FLR+4.9R+12.8D+7.94623Yes
INR+14.0R+19.9D+5.953Yes
MAD+23.0D+19.8D+3.2107Yes
MDD+12.5D+11.8D+0.72414Yes
MER+23.4R+23.8D+0.554Yes
MID+4.0D+0.3D+3.79941Yes
MND+13.2D+15.7R+2.5147Yes
MOR+9.4R+13.7D+4.3147Yes
MSR+16.4R+25.6D+9.211Yes
MTR+3.4R+7.1D+3.72013Yes
NDR+18.5R+32.9D+14.464Yes
NJD+18.9D+9.6D+9.276Yes
NMD+11.2D+10.1D+1.1117Yes
NVD+6.2D+1.6D+4.65924Yes
NYD+21.1D+18.3D+2.895Yes
OHR+0.1R+3.6D+3.53522Yes
PAD+3.3R+0.2D+3.512847No
RID+15.4D+20.0R+4.754Yes
TNR+22.0R+29.6D+7.7104Yes
TXR+3.6R+8.5D+4.94621Yes
UTR+30.6R+30.8D+0.153Yes
VAD+9.7D+8.9D+0.81812Yes
WAD+16.8D+18.4R+1.774Yes
WID+3.0D+0.8D+2.18435Yes
WVR+11.8R+41.0D+29.211Yes
WYR+47.2R+51.0D+3.811Yes