Data & Results

The data and results from the Treasure State 2018 Election Surveys administered by the HELPS Lab at Montana State University - Bozeman were made available to the public in July 2019 in a comprehensive manner. The posted files include:

The dataset is available in STATA format through OPEN ICPSR, which hosts all the documents above, as well. The suggested citation for these data is:

Parker, D. C. W., Raile, E. D., Guenther, S., & Shanahan, E. A. (2019). 2018 Montana Election Surveys (MSU-MTN) [Data file]. Retrieved from 

Post-Election Survey Results

Available materials for the post-election survey include:

Pre-Election Survey Results

Available materials for the pre-election survey include:


Brief Summary of Methods

The MSU-MTN pre-election survey was conducted by the HELPS Lab of Montana State University-Bozeman between September 15 and October 6, 2018. The population for the poll was Montana voters who registered by August 14, 2018. We stratified the sample by state house districts and then drew a random sample of 10,400 voters proportionally from these strata. Sampled individuals received a questionnaire by mail and were asked to return the questionnaire via a self-addressed stamped envelope. Respondents returned 2,079 surveys, a response rate of slightly over 20% based on 10,215 deliverable addresses.

The population size was 686,791 registered voters. This resulted in a margin of error (MOE) of approximately +/- 2 percentage points. We weighted the data by age, media market, marital status by gender, and education to match U.S. Census Bureau data on registered Montana voters. We also weighted on 2016 presidential vote choice to match vote returns reported by the Montana Secretary of State.

The MSU-MTN post-election survey was similarly conducted by the HELPS Lab of Montana State University-Bozeman between November 8 and December 14, 2018. Researchers used a panel design, meaning they re-surveyed individuals who had completed the pre-election questionnaire. Respondents returned 1,424 completed questionnaires for a response rate of approximately 69%. The population of registered voters at the time of the election was 711, 844, which produced an overall MOE of approximately +/- 2.6 percentage points. The weights remained the same except for replacing 2016 presidential vote choice with 2018 Senate vote choice.

These polls were funded jointly by the Montana Television Network and Montana State University. If you have questions concerning the survey methods, please contact the HELPS Lab (