Ruben L. Bach, Carina Cornesse, Jessica Daikeler
Equipping the Offline Population with Internet Access in an Online Panel. Does It Make a Difference?

Journal of Survey Statistics and Methodology, In Press: (publ. online before print)
ISSN: 2325-0984 (print), 2325-0992 (online)

Online panel surveys are often criticized for their inability to cover the offline population, potentially resulting in coverage error. Previous research has demonstrated that non-internet users in fact differ from online individuals on several sociodemographic characteristics. In attempts to reduce coverage error due to missing the offline population, several probability-based online panels equip offline households with an internet connection and a simple computer or tablet. However, the question remains whether the recruitment of offline individuals for an online panel leads to substantial changes in survey estimates. That is, it is unclear whether estimates derived from the survey data are affected by the differences between the groups of online and offline individuals. Against this background, we investigate how the inclusion of the previously offline population into the German Internet Panel affects various survey estimates such as voting behavior and social engagement. Overall, we find little evidence for the claim that equipping otherwise offline individuals with online access affects the estimates derived from previously online individuals only.