Internet Coverage Bias in Web Surveys in Europe

Abstract

The use of web surveys has increased over the last decades in an attempt to reduce survey costs and maximise response rates; this trend has accelerated during the Covid-19 pandemic, when social distancing measures impede face-to-face data collection. Despite the widespread use of web surveys, the uncomplete Internet coverage may still pose a threat to data quality. Using large scale probability-based Eurobarometer data from 2010-2019 we: i) describe the trend in Internet coverage rate across Europe, ii) investigate demographic and socio-economic differences between the Internet and non-Internet population, iii) explore variation over time and across countries in Internet coverage bias, and iv) assess whether countries’ socio-economic context is associated with Internet coverage bias. We find that a non-negligible share of the population does not use the Internet and Internet coverage varies widely across Europe. In addition, we document that coverage bias: decreases over time for most of the variables considered; seems more pronounced in age, education, and life satisfaction, and negligible in other variables; and is associated with countries’ socio-economic context.