Survey Methods

Similar methodology was used in each Public Policy Institute of California (PPIC) Statewide Survey, with respondents selected at random from a computer-generated sample of listed and unlisted telephone numbers. In June 2000, June 2002, and July 2003, the sample included approximately 2,000 California adult residents, and interviews were conducted in English or Spanish, according to respondents’ preferences. In July 2004, July 2005, and July 2006, the sample was expanded to include approximately 2,500 adult residents, and interviews were conducted in five languages (English, Spanish, Chinese [Mandarin or Cantonese], Korean, and Vietnamese). Interviews in each survey took an average of twenty minutes to complete. We used recent U.S. Census and state figures to compare the demographic characteristics of the survey sample with characteristics of California’s adult population. The survey samples were closely comparable to the census and state figures. Survey data were statistically weighted to account for any demographic differences.