KFF COVID-19 Vaccine Monitor: MAGA Republicans’ Relationship With COVID-19 Vaccines

This KFF Health Tracking Poll/COVID-19 Vaccine Monitor was designed and analyzed by public opinion researchers at KFF. The survey was conducted October 31- November 7, 2023, online and by telephone among a nationally representative sample of 1,301 U.S. adults in English (1,222) and in Spanish (79). The sample includes 1,016 adults (n=52 in Spanish) reached through the SSRS Opinion Panel either online (n=991) or over the phone (n=25). The SSRS Opinion Panel is a nationally representative probability-based panel where panel members are recruited randomly in one of two ways: (a) Through invitations mailed to respondents randomly sampled from an Address-Based Sample (ABS) provided by Marketing Systems Groups (MSG) through the U.S. Postal Service’s Computerized Delivery Sequence (CDS); (b) from a dual-frame random digit dial (RDD) sample provided by MSG. For the online panel component, invitations were sent to panel members by email followed by up to three reminder emails.

Another 285 (n=27 in Spanish) interviews were conducted from a random digit dial telephone sample of prepaid cell phone numbers obtained through MSG. Phone numbers used for the prepaid cell phone component were randomly generated from a cell phone sampling frame with disproportionate stratification aimed at reaching Hispanic and non-Hispanic Black respondents. Stratification was based on incidence of the race/ethnicity groups within each frame.

Respondents in the phone samples received a $15 incentive via a check received by mail, and web respondents received a $5 electronic gift card incentive (some harder-to-reach groups received a $10 electronic gift card). In order to ensure data quality, cases were removed if they failed attention check questions in the online version of the questionnaire, or if they had over 30% item non-response, or had a length less than one quarter of the mean length by mode.  Based on this criterion, one case was removed.

The combined cell phone and panel samples were weighted to match the sample’s demographics to the national U.S. adult population based on parameters derived from the Census Bureau’s 2022 Current Population Survey (CPS), 2021 Volunteering and Civic Life Supplement data from the CPS, and the 2023 KFF Benchmarking survey with ABS and prepaid cell phone samples. The demographic variables included in weighting for the general population sample are sex, age, education, race/ethnicity, region, education, civic engagement, internet use, and political party identification by race/ethnicity.  The sample of registered voters was weighted separately to match the U.S. registered voter population using the parameters above plus recalled vote in the 2020 presidential election by county quintiles grouped by Trump vote share. Both weights take into account differences in the probability of selection for each sample type (prepaid cell phone and panel). This includes adjustment for the sample design and geographic stratification of the cell phone sample, within household probability of selection, and the design of the panel-recruitment procedure.

The margin of sampling error including the design effect for the full sample and registered voters is plus or minus 4 percentage points. Numbers of respondents and margins of sampling error for key subgroups are shown in the table below. For results based on other subgroups, the margin of sampling error may be higher. Sample sizes and margins of sampling error for other subgroups are available by request. Sampling error is only one of many potential sources of error and there may be other unmeasured error in this or any other public opinion poll. KFF public opinion and survey research is a charter member of the Transparency Initiative of the American Association for Public Opinion Research.