PollingSource Logo

PollingSource

The number one source for political election data

Polling Trends
Senate House Governors Primaries Data Generic Ballot Pollsters Analysis Login Subscribe

← All pollster records

Southern Illinois University Paul Simon Public Policy Institute

5 scored general-election polls (2014–2018) , each measured against the certified result. How to read these numbers: methodology.

Record by cycle

CyclePollsAvg. ErrorLeanWinner Called
2018 1 6.3 pts D+6.3 100%
2016 2 4.2 pts D+3.5 100%
2014 2 1.3 pts D+0.9 100%

Every scored poll

DateRacePoll MarginActualErrorCalled It
2018-09-26 IL Governor D+22.0 D+15.7 6.3 ✓
2016-09-29 IL President D+24.8 D+17.1 7.7 ✓
2016-09-29 IL Senate D+14.4 D+15.1 0.7 ✓
2014-10-04 IL Governor R+1.7 R+3.9 2.2 ✓
2014-10-04 IL Senate D+10.4 D+10.9 0.5 ✓

Margins shown as party lead (D+/R+); for non-D-vs-R matchups the margin is first-listed candidate minus second. Historical scored-poll data for cycles through 2023 from FiveThirtyEight's pollster-ratings dataset (CC-BY-4.0); 2024 scored by PollingSource. This record never changes what enters the PollingSource average.

Support Independent Election Data PollingSource is free and non-partisan. Your donation helps us continue providing accurate election data.

© 2026 Innovative Research and Data Solutions, LLC. All rights reserved.

Data updated regularly from public polling sources.

As an Amazon Associate, PollingSource earns from qualifying purchases.

Methodology • Pollster Records • Privacy Policy • Terms of Service