It's quite a unclear topic imho, that's why I'm curious if it was tried and wether it worked or not.
"‘personal data’ means any information relating to an identified or identifiable natural person (‘data subject’); an identifiable natural person is one who can be identified, directly or indirectly, in particular by reference to an identifier such as a name, an identification number, location data, an online identifier or to one or more factors specific to the physical, physiological, genetic, mental, economic, cultural or social identity of that natural person;"
I guess interview notes would fall into this category as well. it's related to a identifiable `data subject` and related to his traits. e.g. "John Smith is bad at math and he hates pencils"