The increase in mobile phone ownership – and mobile-phone-only ownership – has changed the sampling frame for fixed telephone surveys, such as the Flash Eurobarometer, with a consequent impact on coverage bias. In this paper, however, we will illustrate – using data from the Flash Eurobarometer – that the increased use of mobile telephones has not only had an impact on non-coverage and non-coverage bias, but also on the amount of non-response and non-response bias.

The Flash Eurobarometer, commissioned by the European Commission and conducted by Gallup Europe, is a tool to measure attitudes and opinions of EU citizens in the  27 Members States of the European Union. Gallup Europe has conducted more than 30 EU-wide telephone surveys (with over 350,000 interviews) on subjects from the Euro to consumer protection, and from higher education to energy policies.

After a short description of the main features of the European phone market – characterised by high mobile phone penetration rates – and the rising impact of mobile-phone-only households, we describe the approach adopted in the Flash Eurobarometer to deal with these changes in the sampling frame for fixed telephone surveys. In Austria and Finland, a dual frame sampling approach of fixed and mobile phone numbers was adopted to evaluate the effects of changes in mobile phone use on non-coverage bias in fixed telephone surveys. In the second, and most important, part of the paper, we then discuss our findings of this evaluation, however, in terms of non-response bias, presenting proof  of the link between non-coverage and non-response bias as a consequence of changes in mobile phone use in Europe.