ORANGE COUNTY ANNUAL SURVEY

Methodology

The Orange County Annual Survey, UCI was co-directed by Mark Baldassare, professor and chair of urban and 
regional planning and, and Cheryl Katz, research associate. The random telephone survey included 1,012 
Orange County adult residents interviewed from August 26 to September 2. We follow the methodology used 
in the 10 previous surveys. 

Interviewing was conducted on weekend days and weekday nights, using a computer-generated random sample 
of telephone numbers. Within a household, adult respondents were randomly chosen for interview. Each 
interview included 93 questions and took an average of 20 minutes to complete. The interviewing was 
conducted in English and Spanish, as needed. 

The completion rate for the survey was 64 percent. This rate is consistent with earlier Orange County 
Annual Surveys. Of the telephone numbers called, 21 percent resulted in completed interviews and 11 
percent were refusals. The field work was conducted by Interviewing Services of America of Van Nuys, CA. 

For analysis, we statistically weighted the sample to represent the actual regional distribution of 
Orange County residents, as has been done in previous surveys. The 1990 U.S. Census population figures by 
city were reviewed for this purpose. 

The sampling error for this survey is +/- 3 percent at the 95 percent confidence level. This means that 
95 times out of 100, the results will be within 3 percentage points of what they would be if all adults 
in Orange County were interviewed. The sampling error for any subgroup would be larger. Sampling error is 
just one type of error to which surveys are subject. Results may also be affected by question wording, 
survey timing and survey design.