Also, quoting friom the GDPR, art. 4
"‘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"