The combined results have been weighted to adjust for the fact that not all survey respondents were selected with the same probability, to address the implications of sample design, and to account for systematic non-response along known population parameters. The first weighting stage addressed differences in probability of selection for the AmeriSpeak Panel and accounted for differential non-response to the AmeriSpeak screening interview. At this stage, an adjustment was also made to account for the oversampling of lower-income panelists and to account for differential non-response to the survey screening interview.

Source: Los Angeles Times May 02, 2019 09:56 UTC