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

Thomas Partners Strategies/Øptimus

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

Record by cycle

CyclePollsAvg. ErrorLeanWinner Called
2018 8 14.8 pts R+14.8 100%

Every scored poll

DateRacePoll MarginActualErrorCalled It
2018-10-26 CA Governor D+13.4 D+23.9 10.5 ✓
2018-10-19 CA Governor D+12.5 D+23.9 11.4 ✓
2018-10-13 CA Governor D+7.4 D+23.9 16.5 ✓
2018-10-06 CA Governor D+11.6 D+23.9 12.3 ✓
2018-09-29 CA Governor D+5.0 D+23.9 18.9 ✓
2018-09-22 CA Governor D+11.0 D+23.9 12.9 ✓
2018-09-15 CA Governor D+4.1 D+23.9 19.8 ✓
2018-09-08 CA Governor D+8.2 D+23.9 15.7 ✓

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