Establishing a Baseline: Bringing Innovation to the Evaluation of Cross-National Probability-Based Online Panels

A number of countries in Europe and beyond have established online or mixed mode panels with a web component based upon probability samples. This paper aims to assess the first ever attempt to do this cross-nationally using an input harmonised approach representing a major innovation in cross-national survey methodology. The European Social Survey established a panel using the face-to-face interview as the basis for recruitment to the panel. This experiment was conducted in Estonia, Slovenia and Great Britain using an input harmonised approach to the design throughout something never done before across multiple countries simultaneously. The paper outlines how the experiment was conducted. It then moves on to compare the web panel respondents to the ESS achieved face-to-face sample in each country, as well as comparing the web panel achieved sample to external benchmarks. Most importantly, since the literature is very scarce, the differences in attitudinal and behavioural characteristics are also assessed. By comparing the answers of the total achieved sample in the ESS to the subset who also answered the CRONOS web panel we assess changes in representativeness and substantive answers without confounding the findings with other changes such as mode effects. This approach is only possible where ‘piggybacking’ recruitment has been used. This in itself is rare at the national level but this is the first time survey methodologists have employed this cross-nationally allowing such an analytical approach. Our findings suggest that the CRONOS sample is not too divergent from the target population and to the ESS with the exception of the oldest age groups. However, there are cross-national differences suggesting cross-national comparability might be different when compared to estimates from a face-to-face survey.