Data Note: A Look At Swing Voters Leading Up To The 2020 Election

This KFF Health Tracking Poll- Swing Voters was designed and analyzed by public opinion researchers at the Kaiser Family Foundation (KFF). The data from this topline is from two KFF Health Tracking Polls conducted May 30-June 4, 2019 and July 18-23, 2019, among a nationally representative random digit dial telephone sample of 2,402 adults ages 18 and older, living in the United States, including Alaska and Hawaii (note: persons without a telephone could not be included in the random selection process). To see the methodology for each poll, please visit the following: June 2019 available at and July 2019 available at

The combined landline and cell phone sample for each month was weighted to balance the sample demographics to match estimates for the national population using data from the Census Bureau’s 2017 American Community Survey (ACS) on sex, age, education, race, Hispanic origin, and region along with data from the 2010 Census on population density. The sample was also weighted to match current patterns of telephone use using data from the July-December 2018 National Health Interview Survey. The weight takes into account the fact that respondents with both a landline and cell phone have a higher probability of selection in the combined sample and also adjusts for the household size for the landline sample, and design modifications, namely, the oversampling of prepaid cell phones and likelihood of non-response for the re-contacted sample. All statistical tests of significance account for the effect of weighting.

The margin of sampling error including the design effect for the full sample of registered voters 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. Kaiser Family Foundation public opinion and survey research is a charter member of the Transparency Initiative of the American Association for Public Opinion Research.


N (unweighted)


June KFF Health Tracking Poll- Registered voters


±4 percentage points

July KFF Health Tracking Poll- Registered voters


±4 percentage points

Total registered voters


±3 percentage points




Total swing voters


±5 percentage points


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