Numerous national and international survey programs, including general population surveys, have been shifting their mode of data collection from face-to-face to self-completion designs. Push-to-web designs are a particularly promising approach that, however, also introduces methodical challenges. In this paper, we address several of these challenges by providing in-depth empirical analyses of selection and measurement effects from a cross-sectional and longitudinal perspective (time trends across years and survey modes). We use data from the Social Survey Austria (SSA) 2018, 2023 and 2024, including questions from the Austrian implementation of the International Social Survey Programme (ISSP). The survey transitioned from Computer-Assisted Personal …