Data Exports Unpacked: A User Study on Visualizing Exports under Article 20 GDPR (Long Version)

Although the General Data Protection Regulation (GDPR) ensures the right to data portability, standard export formats such as JSON or CSV are often difficult for users to interpret. In this work, we conducted a large-scale study with 266 participants and examined the engagement with a self-developed visualization tool. More specifically, participants were assigned to a control group using raw exports or to one of three groups using visualizations with varying levels of detail. The study setup allows us to investigate how different forms of personal data visualizations influence individuals' perceptions of data exports under the GDPR and shape their attitudes toward and behavioral intentions regarding personal data processing. Results show richer visualizations significantly enhance perceived comprehension and usability of data exports. Tool users reported heightened privacy awareness and a higher likelihood of adjusting privacy settings. We further identify design features that drive perceived usefulness. These findings highlight opportunities to strengthen transparency and inform the design of privacy dashboards that better support individual control over personal data.