The findings of the Los Angeles Times/USC College of Letters, Arts and Sciences poll are based on a random sample survey of 1,506 registered voters in the state of California conducted from May 19 to 26, 2010. All interviews were done by telephone using live interviewers from the Interviewing Service of America facility in Van Nuys.
Voters were randomly selected from a list of registered voters statewide. Respondents were reached on a landline or cellphone depending on the numbers they had designated on their voter registrations. The percentage of cellphone respondents in this study matches the percentage of those who list their cellphone on the voter file. Bilingual dialers gave respondents the option of taking the survey in English or Spanish. Up to five attempts were made to reach and interview each randomly selected voter.
In order to include a wider range of questions in the time allocated for this study, some batteries of related questions were split into random half-samples of 753 voters each, or random third samples of 502 voters each.
Upon completion of the interviewing, the results were weighted slightly to more accurately reflect the total population of registered voters throughout the state. Weighting was done to regional and demographic characteristics according to known census estimates and voter-file projections; party registration was weighted to match the most recent 2010 report from the California Secretary of State.
The maximum sampling error for results based on the overall sample of 1,506 registered voters is +/- 2.6 percentage points at the 95% confidence level. The margin of sampling error for the findings from each random half-sample of 753 registered voters is +/- 3.6 percentage points and the margin of sampling error for each third split is +/- 4.5 percentage points.
This survey was conducted for the Los Angeles Times and the University of South California College of Letters, Arts and Sciences by Greenberg Quinlan Rosner in conjunction with American Viewpoint, both based out of Washington, DC.