Practices vary widely by facility, but yes, technically the psychologist can look up individual patients and then assign themselves to see them---but this would be a lot of admin time with some of the software or paper charts to navigate who has the appropriate insurance and would likely benefit from an initial eval, whereas some facilities have a breakdown of who has which insurance, mental illness/symptoms. Per my understanding, the colleague isn't supposed to just assign themselves to everyone just because they can, hence why social services plays a role (this client has had X problem lately and would be appropraite to see based on insurance, etc.). The psychologist doesn't have access to a census of patients, and some facilities don't even have electronic charts, as I mentioned. When said colleague was hired, they were told that social services was supposed to handle referrals.