Anonymization is difficult and sometimes impossible because reidentification attacks are extremely difficult to prevent. Anonymization is much more complex than

Anonymization is difficult and sometimes impossible because reidentification attacks are extremely difficult to prevent. Anonymization is much more complex than people typically assume; see [1,2] for surveys. The more data you release, the more difficult it is to ensure that subjects cannot be reidentified by combining the "anonymized" dataset with other publicly available data. Important note: It's not just a case of putting in the work and being willing to share. There are impossibility results in this space. That is, there are reasonable formal threat models for which it is mathematically impossible to release any version of the dataset that is (a) useful (ie contains enough data to replicate findings) and (b) not subject to unacceptable levels of reidentification. I am generally in favor of releasing data and code/spreadsheets, but anything involving patients becomes difficult quickly. There are also reasonable middle grounds between "no access for anyone" and "throw it in a public s3 bucket". E.g., making data more available to researchers and medical practitioners -- or even sufficiently interested & motivated members of the public -- but under strict data handling rules, enforceable audit trails, and legal consequences for being reckless with sensitive patient data. Hell, odds are better than even that your employer made you sign a document that would allow them to sue you into oblivion for forwarding some sure-to-be-doomed product launch draft to the wrong person. Being at least that careful with fine-grained medical data on hundreds/thousands of patients isn't exactly unreasonable... Drawing a hard line on 100% complete, anonymous, and consequence-free access to troves of patient data isn't a reasonable position. [1] https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0028071&type=printable https://journals.plos.org/plosone/article/file?id=10.1371/jo... [2] https://www.ccs.neu.edu/home/jullman/cs7880s17/DSSV.pdf https://www.ccs.neu.edu/home/jullman/cs7880s17/DSSV.pdf