VotePredictor
past elections

Illinois House

Sean Casten (D) vs Peter J. Roskam (R)

Actual result
D+7.2
Final polls said
D+1.2
1 late poll · ✓
Model predicted
R+3.0
Winner
Dem

"Final polls said" averages polls from the last ~3 weeks — the call right before the vote, and how pollsters are rated. The model's prediction is walk-forward (trained only on earlier races).

Final rankings

How everyone who called this race did, ranked — VotePredictor shown inline (★).

Pollsters — each pollster's final poll vs the result

#PollsterFinal callMissCalled
1Garin-Hart-Yang Research GroupD+5.02.2
2The New York Times/Siena CollegeD+1.25.9
3VotePredictorR+3.010.2

Forecasters — pre-election win probability, scored by Brier

#ForecasterWin probBrierCalled
1Cook PoliticalDem 75%0.062
2Sabato's Crystal BallDem 75%0.062
3FiveThirtyEightDem 62%0.144
4DDHQ/Decision DeskDem 57%0.189
5The EconomistDem 56%0.195
6VotePredictorDem 50%0.247

Polls (3)

PollsterDatenPollMiss
The New York Times/Siena College2018-10-23497D+1.26
Garin-Hart-Yang Research Group2018-09-30400D+5.02
Garin-Hart-Yang Research Group2018-09-09402D+3.04