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2017 PUBLIC OPINION SURVEY METHODOLOGY
As part of Forecast LA’s unique approach to forecasting in the Los Angeles region, the Center for the Study of Los Angeles conducted an outlook survey. The Los Angeles Public Opinion Survey involved 20-minute telephone sessions and online surveys with more than 2,400 adults (1,800 phone and 600 online) living in Los Angeles County. Survey respondents were asked about quality-of-life perceptions, personal economic wellbeing, economic concerns, overall life satisfaction, and various civic issues. Los Angeles Public Opinion Survey Sampling Since the primary purpose of this study was to gather representative input from adult residents within the Los Angeles region, an initial random digit dial (RDD) sample was employed. The RDD sample was drawn by determining the active phone exchanges (the first three numbers of a seven-digit phone number) and blocks with a given sampling area (in this case, by the zip codes that comprise the county). A random list of all active residential and cell phone numbers in the area was produced. This method included both listed and unlisted phone numbers. Listed samples were used to meet particular quotas for racial/ethnic categories and geographic location. The online portion was comprised of responses from double opt-in respondents who have agreed to participate in surveys. Real-time sampling and survey publishing services were also used to target respondents outside of the initial reach. Finally, listed samples were used to fill gaps within racial/ethnic and geographic quotas. For all methods, adult respondents in LA County were targeted and then randomly selected within their group.
The protocol for this study involved asking potential respondents a series of questions, referred to as screeners, which were used to ensure that the person lived within the county and was at least 18 years old. The target sample size was 1,200 residents from the city of Los Angeles and 1,200 residents from Los Angeles County who live outside the city of LA. The first quota was a random digit dialing of approximately 750 residents (with 66% cell phone). The online survey ran concurrently with a target sample size of 600 respondents. The remaining racial/ethnic and geographic quotas were determined based on the fallout: 400 African American residents, 600 Asian residents, 400 residents from the San Fernando Valley (only within the city of Los Angeles) and 400 residents from the San Gabriel Valley. Given the demographic proportion of Latino and white residents in the region, as expected, both groups naturally fell out from the initial wave of online and phone respondents.
Telephone surveys were conducted the first four full weeks in January 2017 and first two weeks in February between the hours of 4:30pm and 9pm during the week, 10am to 4pm on Saturday, and 10am to 5pm on Sunday. The survey was translated into Spanish, Mandarin, and Korean. Translators who spoke Spanish, Mandarin, and Korean were available to conduct interviews for residents who only spoke, or were more comfortable speaking any of those languages. The online survey ran from January 13 to January 26 and was available in English and Spanish. The margin of error is ±3.0% for the entire sample of 2,404 residents.