2020 Treasure State (Montana) Election Surveys

The Treasure State 2020 Pre-Election Survey was conducted by the
HELPS Lab of Montana State University-Bozeman between September 14 and October 2,
2020. The original population for the survey was Montana voters who registered by
August 20, 2020, and were deemed active by the Montana Secretary of State. We
stratified the sample by state house districts, and then drew a random sample
of 9,000 voters proportionally from these strata. Sampled individuals received
a questionnaire by mail and were asked to return the questionnaire via a prepaid
business reply envelope. Respondents returned 1,789 surveys, a response rate of
20.2% based on 8,836 deliverable addresses. The Treasure State 2020
Post-Election Survey, also conducted by the HELPS Lab, used a panel design that
returned to the individuals who responded to the Pre-Election Survey. This survey was in the field from November 4-25, 2020. Of the 1,789 original respondents, 1,069
completed the post-election questionnaire, for a response rate of 59.8%. The
procedures for the Post-Election Survey otherwise paralleled those for the
Pre-Election Survey.

<br><br>The number of individuals voting in the 2020 general election in
Montana was 612,075, according to information from the Montana Secretary of
State. We have adjusted the overall survey margin of error (MoE) for design
effect owing to our subsequent use of weights in calculating results. This
adjustment has the consequence of making the margin of error substantially
larger than it otherwise would be. For the pre-election sample, this results in
a MoE of <b>+/- 3.7</b> percentage points, using a confidence level of 95% and
a response distribution of 50% (the most conservative estimate) with the given population
size. For the post-election sample, the corresponding MoE is <b>+/- 6.0</b>
percentage points. We note that these figures are overall approximations given
sampling stratification and different response options and response patterns
for specific questions. <br>

<br>This project was funded by over 100 individual donors to the Montana State University Alumni
Foundation and by Montana State University.