Keywords: Methodological challenges and improvements, including in the areas of sampling, measurement, survey design and survey response or non-response

A number of countries in Europe and beyond have established on-line or mixed mode panels based upon probability samples. The European Social Survey ERIC has followed this approach and applied it for the first time in a cross-national environment. Respondents were recruited to an on-line panel at the end of the main ESS face-to-face interview and then completed bi-monthly interviews over a 12-month period. This was a proof of concept experiment in Estonia, Slovenia and the United Kingdom.
This paper will outline how the experiment was conducted and present initial response rates in each country. It will then move on to compare the web panel respondents to the achieved face-to-face sample in each country as well as comparing those achieved samples to external benchmarks such as the census or other high quality national and comparative surveys. Comparisons with other on-line probability panels will also be drawn where relevant. Variables for comparison will include demographics such as gender, age and education, external benchmarks such as car ownership and more subjective survey measures such as self-reported health.