Survey response rates in European comparative surveys: a 20-year decline irrespective of sampling frames or survey modes

This paper assesses trends in three survey outcome rates within four prominent crossnationalcomparative surveys conducted in European countries in the 21st century: theEuropean Quality of Life Survey, the European Social Survey, the European ValuesStudy, and the International Social Survey Programme. These projects are recognisedfor their high-quality sampling and fieldwork procedures, extensive track records, andcommitment to rigorous methodological standards. The analysis is based on 753national surveys conducted on probability samples of the general population in 36European countries from 1999 to 2018. We investigated whether two essential surveycharacteristics, namely sampling frames and data collection modes, moderated thedecrease of survey outcome rates over time. To analyse these relationships, thesurvey year was included as the explanatory variable, and we applied multi-level linearregressions with surveys nested within countries. Additionally, the project name wasincorporated as a fixed factor, and the sampling frame and mode of data collectionwere control variables for the effect of time. Our study provides valuable insights intothe challenges of conducting high-quality Pan-European cross-national comparativesurveys over nearly two decades. We observed a consistent decline in survey outcomerates, irrespective of country or project. Neither the sampling frame nor the datacollection mode moderated this decline. Hence, even though personal register samplesand Face-to-Face interviews are often regarded as enhancements to overall surveyquality, their application does not effectively counter the factors causing a decline insurvey outcome rates.