It's a scavenger hunt: Usability of Websites' Opt-Out and Data Deletion Choices
https://doi.org/10.1145/3313831.3376511
Method
"We conducted an in-lab user study with 24 participants to explore the usefulness and usability of privacy choices offered by websites."
Population
"a set of nine websites that differed in terms of where and how these choices were presented"
What it does not show
Measures whether a person could navigate to and submit a request, not whether the backend deleted anything. Small, single-jurisdiction lab sample across nine sites — not an audit of compliance rates at scale.
Hana Habib, Sarah Pearman, Jiamin Wang, Yixin Zou, Alessandro Acquisti, Lorrie Faith Cranor, Norman Sadeh, Florian Schaub
Participants routinely failed to find the correct path to opt-out and deletion controls and misunderstood what written requests required. Controls in account settings were markedly easier than those buried in privacy policies, and a substantial share fell back on help pages or emailing support to do something the site nominally offered as self-service.
Tier III: In-lab usability study with 24 participants across nine real sites. Real production interfaces, small sample, no comparison group.