Probability-Based vs. Non-Probability Online Panel Surveys: Assessing Accuracy, Response Quality, and Survey Professionalism

While probability-based surveys remain the standard in academic research, non-probability online panels are increasingly used due to their lower costs and faster data collection. This study compares two post-election online panel surveys conducted in Austria—one based on probability sampling (Digitize!) and the other on non-probability sampling (AUTNES)—across three dimensions: accuracy, response quality, and survey professionalism. Both surveys demonstrate a high level of accuracy relative to external benchmarks, with the non-probability sample showing some advantage in reaching non-voters. Response quality is broadly similar; although non-probability respondents exhibit slightly more satisficing behavior, differences in attention check results, item non-response, and internal consistency are minimal. As expected, non-probability respondents report more frequent survey participation and slightly greater financial motivation. However, intrinsic motivations are equally important in both groups, and digital skills and device usage are comparable. Overall, the findings suggest that non-probability surveys can yield data quality comparable to that of probability-based approaches and may be suitable for scientific research when paired with appropriate quality assessments.