KFF/The Undefeated Survey on Race and Health

The KFF/The Undefeated Survey on Race and Health is based on interviews conducted in English and Spanish with a nationally representative sample of 1,769 U.S. adults ages 18 and older, including an oversample of Black adults. Specifically, the survey oversampled mothers, people younger than 30, and college-educated respondents who identify as Black or African American. The survey was conducted August 20-September 14, 2020, using a hybrid design that combined a stratified, dual-frame (landline and cell phone) random digit dial (RDD) telephone sample (N=1,303) with a probability-based web/phone panel (N=466). Sampling, data collection, weighting, and tabulation were managed by SSRS of Glen Mills, PA, in close collaboration with Kaiser Family Foundation researchers. Teams from KFF and The Undefeated worked together to develop the questionnaire and analyze the data, and both organizations contributed financing for the survey. Each organization is solely responsible for its content.

For the RDD sample, computer-assisted telephone interviews were conducted with respondents reached by cell phone and landline. To efficiently obtain a sample of Black respondents, the RDD sample was stratified to oversample areas with a high population share of Black adults. The telephone sample also included 226 respondents reached by calling back Black respondents (predominantly those who previously indicated they were college graduates or under age 30) who had previously completed an interview on the SSRS Omnibus poll, a weekly dual-frame RDD telephone survey. Both the RDD landline and cell phone samples were provided by Marketing Systems Group (MSG). For the landline sample, respondents were selected by asking for the youngest adult male or female currently at home based on a random rotation. If no one of that gender was available, interviewers asked to speak with the youngest adult of the opposite gender. For the cell phone sample, interviews were conducted with the adult who answered the phone.

Panel interviews were conducted using the SSRS Opinion Panel, a representative probability-based panel of adults ages 18 and over living in the United States, recruited using the SSRS Omnibus poll and through address-based sampling (ABS). Panel members who do not have internet access complete surveys via telephone, and internet users complete surveys via the web (for the current study, 38 panel respondents completed via phone and 428 completed via web). A total of 233 Black panelists were included, targeting those who previously indicated they were mothers of children under age 18, college graduates, or under the age of 30. In addition, 233 non-Black panel members were included so that any differences in the mode of data collection would not impact the Black sample alone. In total (including the RDD sample and phone interviews from the panel sample), 283 interviews were completed via landline and 1,058 via cell phone (including 749 who could not be reached via landline); 428 interviews were completed via web.

The combined landline, cell phone, and web sample was weighted to match the sample demographics to estimates for the national population. A multi-stage weighting process was used to adjust for the fact that not all survey respondents were selected with the same probabilities and to account for systematic non-response. In the first weighting stage, adjustments were made to 1) correct for the oversampling of different groups; 2) account for the fact that respondents with both a landline and cell phone have a higher probability of selection in the RDD sample; 3) adjust for likelihood of non-response for the re-contacted sample; 4) match estimates of the population (Black and non-Black) that do not use the internet based on estimates from the Pew Research Center; and 5) match current patterns of telephone use (Black and non-Black) according to the June-December 2019 National Health Interview Survey. In the second weighting stage, the sample was weighted (separately for Black and non-Black respondents) to match demographics of the adult U.S. population using data from the Census Bureau’s 2018 American Community Survey (ACS) on age by gender, education, race and Hispanic origin (for non-the non-Black sample), parent status (by gender), metropolitan status, and Census region. Weights were then trimmed separately for the Black and non-Black samples, and in the final stage, the samples were combined and adjusted to ensure the proportion of Black respondents in the total sample would equal their share of the adult population. All statistical tests of significance account for the effect of weighting.

The margin of sampling error including the design effect for the full sample is plus or minus 3 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. Note that sampling error is only one of many potential sources of 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.