In the question What is the status of Freudian publications in psychological journals?, one user says:
I think your first challenge would be in labeling a paper as "Freudian" or not. There are many areas of research motivated by Freud and that may be labeled Freudian or Freud-inspired in some contexts, but the work itself uses a more scientific approach and need not be weighed down by Freud's own lack of rigor.
Another one says:
You would need to have an extensive knowledge of psychology paper authors for that @Ooker and I would challenge anyone who would think they know every single author and their affiliation towards particular psychological modalities.
Yet, it's common to say someone belongs to a school: "Alice is a Freudian", "Bob's paper works on humanism", etc. In what ground do those statements hold? Or to this day there is still no reliable method to make those statements concrete?