The last decade has seen some high-quality surveys adopting web as the primary mode for data collection, a trend that has been accelerated due to the pandemic. To reach segments of the population without internet access, most high-quality surveys employ mixed-mode designs, pairing web surveys with an interviewer-administered mode such as face-to-face or telephone. However, the mixed-mode designs entail higher fixed costs than a web-only survey and might introduce measurement differences affecting data comparability. As internet access has grown in the UK to cover almost the whole population and the levels of digital literacy have improved considerably, a critical question is whether it is now feasible to conduct web-only surveys of the general population without compromising representativeness.

This research investigates two key aspects to assess the feasibility of implementing web-only surveys. First, it examines the characteristics of the UK population that remains offline and how they differ from those who use the internet. Second, it evaluates differences between web survey respondents and non-respondents, exploring how these differences affect representativeness. This analysis aims to disentangle the bias due to the offline population from the bias produced by the rest of the web non-respondents. The analysis uses data from the Innovation Panel and the main study of Understanding Society, the United Kingdom Household Longitudinal Study (UKHLS). We use the Innovation Panel, which includes a random subsample of households allocated to a sequential web-first with CAPI follow-up mode design since 2012, to explore the research questions with a longitudinal perspective. Furthermore, we use a larger random subsample of the UKHLS main study that transitioned to a web-first design in 2020 due to the COVID-19 pandemic to investigate the effect of using a web-only design on the representativeness of some subgroups, such as ethnic minorities.

Co-authors

Professor Annette Jäckle; Dr Jonathan Burton; Dr Jamie Moore, University of Essex

Professor Gabriele Durrant, University of Southampton