Online panel providers are confronted with an ever-increasing number of technical devices, operating systems and internet browsers with which panel members access the internet and retrieve emails. Mobile devices such as Smartphones offer a wide variety of innovative research designs by means of new participation modes, interview occasions and data sources. This beneficial “intentional” use of mobile devices as data collection mode is counterbalanced by the potential threat to data quality by “unintentional mobile respondents”.

Unintentional mobile respondents participate in a conventional online survey per mobile device. Especially the limitations inherent to Smartphones in terms of display size and data entry comfort raise concerns regarding the usefulness of mobile participations. But a rejection of mobile survey accesses may decrease the accessibility of surveys causing systematic sample biases.

The few empirical studies available do not yield conclusive results regarding the extent of unintentional mobile participations and their impact on data quality. The paper addresses both validity threats and reports results of four studies conducted in the German section of the online panel of Harris Interactive AG.

Based on its results, the paper comes to the conclusion that unintentional mobile respondents do not inevitably threaten the quality of survey results obtained in online panels. In fact, respondents instructed to participate via Smartphone performed as well as participants taking the survey on a PC in nearly all question and response formats on all quality measures. Furthermore, it took mobile respondents considerably more time to complete the interview, they reported a variety of inconveniences, and many of them completed the survey on a PC against the instruction. Given that mobile participation in a conventional HTML web survey a) does not face major technical hurdles any more but is b) still annoying in terms of usability, the paper recommends the implementation of a transparent and fair survey quality management encouraging panel members to balance pros and cons of thorough mobile survey participation.