The survey findings presented in this release are based on the results of interviews conducted March 1 – 7, 2021. The interviews were conducted at the Center for Opinion Research at Franklin & Marshall. The data included in this release represent the responses of 588 registered Pennsylvania voters, including 269 Democrats, 236 Republicans, and 83 independents.[i] The sample of voters was obtained from Marketing Systems Group. All sampled respondents were notified by mail about the survey. Interviews were completed over the phone and online depending on each respondent’s preference. Survey results were weighted (age, gender, education, geography, and party registration) using an iterative weighting algorithm to reflect the known distribution of those characteristics. Estimates for age, geography, and party registration are based on active voters within the PA Department of State’s voter registration data. Gender and education is estimated using data from the November 2018 CPS Voter Registration Supplement. [ii]
The sample error for this survey is +/- 5.5 percentage points when the design effects from weighting are considered. In addition to sampling error, this poll is also subject to other sources of non-sampling error. Generally speaking, two sources of error concern researchers most. Non-response bias is created when selected participants either choose not to participate in the survey or are unavailable for interviewing. Response errors are the product of the question and answer process. Surveys that rely on self-reported behaviors and attitudes are susceptible to biases related to the way respondents process and respond to survey questions.