Even without the patient's name attached it is easy to identify people because of the necessary metadata in the record. If you expect to get useful information about, for instance lung disease the record will have to contain information about exposure to likely causes, age, occupation, region of the country (possibly town), sex. It will also contain marital status, whether one has children, drinking and smoking habits, weight, ethnicity.

This is pretty close to unique, just like a browser finger print.

See for instance: http://randomwalker.info/publications/no-silver-bullet-de-id...

Anonymize then let the flood gates open.

De-anonymizing medical records strikes me as a fairly easy problem to solve... the information is literally one large biometric database.

There are actually government mandated methods for deidentifcation

https://www.hhs.gov/hipaa/for-professionals/privacy/special-...

> government mandated methods

Is that supposed to imply they work?

Actually, if you read that, they aren't government mandated methods (in the technical sense) there's an option of either using a government-specified safe harbor method or getting an "expert determination" that the data is deidentified.

I should have said "there is a government mandated method, but that's not the only way" It's more of a starting point than anything else. Also if you get HIPAA audited you either have to follow the government way (easiest for broke startups) or go the expert way but that is a bit more costly to prove out.