Western New England University Polling Institute

Massachusetts Statewide Telephone Survey

Conducted in Partnership with MassLive.com and

The Republican newspaper, Springfield, MA

Sept. 28 – Oct. 4, 2012

METHODOLOGY

The Western New England University Polling Institute survey consists of telephone interviews with 567 adults ages 18 and older drawn from across Massachusetts using random-digit-dialing Sept. 28 – Oct. 4, 2012. The sample yielded 516 adults who said they are registered to vote in Massachusetts, and 440 adults who are classified as likely to vote in the Nov. 6, 2012 general election. Unless otherwise noted, the figures in this release are based on the statewide sample of likely voters. The Polling Institute classified likely voters based on voters’ responses to questions about interest in the election, likelihood of voting in the election, ability to identify their polling place, and whether they reported voting in the 2008 presidential election.

The Polling Institute dialed household telephone numbers, known as “landline numbers,” and cell phone numbers for the survey. In order to draw a representative sample from the landline numbers, interviewers first asked for the youngest male age 18 or older who was home at the time of the call, and if no adult male was present, the youngest female age 18 or older who was at home at the time of the call. Interviewers dialing cell phone numbers interviewed the respondent who answered the cell phone after confirming three things: (1) that the respondent was in a safe setting to complete the survey; (2) that the respondent was an adult age 18 or older; and (3) that the respondent was a resident of Massachusetts. The landline and cell phone data were combined and weighted to reflect the adult population of Massachusetts by gender, race, age, and county of residence using U.S. Census estimates for Massachusetts.  Complete results of the poll are available online at www.wne.edu/news. The full text of the questionnaire for this survey is available at www1.wne.edu/pollinginst.

All surveys are subject to sampling error, which is the expected probable difference between interviewing everyone in a population versus a scientific sampling drawn from that population. The sampling error for a sample of 440 likely voters is +/- 4.7 percent at a 95 percent confidence interval. Thus if 55 percent of likely voters said they approved of the job that Scott Brown is doing as U.S. Senator, one would be 95 percent sure that the true figure would be between 50.3 percent and 59.7 percent (55 percent +/- 4.7 percent) had all Massachusetts likely voters been interviewed, rather than just a sample. The margin of sampling error for the sample of 516 registered voters is +/- 4.3 percent at a 95 percent confidence interval. Sampling error increases as the sample size decreases, so statements based on various population subgroups are subject to more error than are statements based on the total sample.  Sampling error does not take into account other sources of variation inherent in public opinion studies, such as non-response, question wording, or context effects.