Width is the Limit – Response Behavior and Data Quality in a Mobile-First Survey

The rise in smartphone use for web surveys requires layout adaptations that ensure consistent and high-quality data collection across devices and survey modes. This study evaluates the effects of a mobile-first survey layout compared to a traditional desktop-first layout in a large-scale, mixed-mode (online and paper) German panel survey. Through a randomized experiment, we examine how layout influences response behavior and data quality across devices and modes, using indicators such as survey duration, item nonresponse, breakoffs, and various forms of satisficing. Results show that while PC/laptop users experienced longer measured durations with the mobile-first layout, this did not affect their subjective experience. The mobile-first layout reduced item nonresponse across most modes and increased variation in responses, especially for matrix questions, without increasing breakoffs or satisficing behaviors. These findings suggest that mobile-first layouts perform equally or better than desktop-first layouts in most aspects of data quality, supporting their adoption in contemporary survey design.