Technological advances in the recent past made it possible for researchers to collect and analyze large amounts of health data at unprecedented scale and speed. For example, fitness trackers and smartwatches produce steady flows of information on individuals’ health. Biomarker data and medical records allow to study individuals at new levels of granularity. The COVID-19 pandemic has highlighted that access to such data for health research and evidence-based public policy decision-making is essential. However, having access to data depends on individuals’ willingness to share their data with others. In this paper, we analyze the factors that may affect the probability of individuals to share their biomarker, health, and sensor data using German survey data and a survey experimental vignette design. We study the impact of data type, recipient, and research purpose on respondents’ willingness to share their data as well as the effects of respondents’ own medical and data sharing history. Overall, participants’ willingness to share biomarker data was higher than the willingness to share other data types. Moreover, those who had shared data before were more willing to do so again. In addition, natural language processing analysis of textual responses capturing respondents’ motives to share their data shows that individuals do understand how valuable their data is for researchers. However, results also underscore that addressing concerns about the protection of data need to be taken seriously. Emphasizing the value of data shared for research and their purpose may help to increase trust and willingness to share data.
