This survey was conducted among 2,097 adults between March 9 and March 29, 2021, by Kantar Public using the PUBLIC Voice panel, a nationally representative mixed-mode panel of randomly recruited and selected individuals residing in the United Kingdom.
Panelists participated via self-administered web surveys (93.0% of respondents) as well as via interviewer-administered telephone surveys (7.0% of respondents). The margin of sampling error for the full sample of 2,097 respondents is plus or minus 3 percentage points.
PUBLIC Voice panelists are initially invited to join via in-person interviewing (face-to-face recruitment) or via mail invitation including a printed URL or paper questionnaire (address-based online sampling recruitment). The mail invitation sample is calibrated to match the higher response rate interview sample across multiple demographic, behavioral and attitudinal domains. These recruitment methods provide national coverage of all UK adults who can be reached at a postal address. This approach ensures representation from both the online and offline UK population. Different methodologies are used to encourage response by online and offline panel members, including multiple contact attempts and reminders. All respondents are given a small incentive for taking the recruitment survey and another incentive for each survey they complete.
The completion rate for this survey is 60.9% of the 3,443 panelists who were invited to complete the survey. Accounting for initial recruitment to the panel (depending on the method of recruitment) as well as panelist availability (nonresponse) and eligibility for this survey, the cumulative response rate for this survey is 5.1%.
The questionnaire was developed by Pew Research Center in consultation with Kantar. The online version of the questionnaire was rigorously tested by Kantar and Pew Research Center researchers to ensure the logic of the instrument (including skip patterns) and that randomizations were working as intended before launching the survey. The survey was fielded in English.
To ensure high-quality data, Kantar performed data quality checks to identify any respondents showing patterns of satisficing. This includes checking for respondents who may have sped through sections as well as straight-lining responses.
The PUBLIC Voice panel uses a three-stage, model-based weighting approach so that the sample results can be used to draw inferences about the population. (The target population for this survey was non-institutionalized persons ages 18 and older, living in the UK.) The stages of weighting account for unequal probabilities in the recruitment survey as well as for nonresponse that occurs at different points in the survey process.
To ensure the final data are representative of UK adults, the sample was balanced to population benchmarks based on the Office for National Statistics 2011 UK Census. The benchmark variables used to balance this survey include age, gender, education and region. While the standard PUBLIC Voice calibration process uses the contemporary UK Labour Force Survey as the benchmark rather than the 2011 Census, a different benchmark was used for this study to maximize compatibility with other Pew Research Center surveys in the UK. There was little difference in outcomes between these two approaches. In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.