Identity of ghosts
The reason is, I suspect, that the methods used do not stand up to scrutiny. It is generally done through historical research. People will find out about previous occupants of a house and then, effectively, guess based on appearance. Things that may prompt the choice of one person over another might be any tragedy affecting a person.
In some cases, the 'identity' of a ghost may be 'well known' to people in an area eg. someone who committed suicide there. However, investigation may find no trace of any such person ever having been there or any suicide.
What OUGHT to be done is for witnesses to look at lots of pictures of similar 'suspects' and be allowed to chose like a police identity parade. Obviously, this may be impractical if pictures are not available, however this does not justify guessing on the flimsiest of evidence.
The very fact that investigators attempt to 'identify' a ghost shows that they accept before they start the theory of 'spirits' or 'recordings'. However, the whole point of paranormal investigation is to establish these points!
I believe most, if not all, identifications of ghosts are entirely spurious.