About this Poll

The survey findings presented in this release are based on the results of interviews conducted June 8 -14, 2015. The interviews were conducted at the Center for Opinion Research at Franklin & Marshall College under the direction of the poll’s Director Dr. G. Terry Madonna, Head Methodologist Berwood Yost, and Project Manager Jacqueline Redman. The data included in this release represent the responses of 556 Pennsylvania registered voters, including 274 Democrats, 210 Republicans, and 72 Independents. The sample of registered voters was obtained from Labels & Lists. Survey results were weighted (gender, region and party registration) using an iterative weighting algorithm to reflect the known distribution of those characteristics as reported by the Pennsylvania Department of State. The sample error for this survey is +/- 4.1 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. Nonresponse 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 proce
ss and respond to survey questions