Re: Who actually makes the decision?
I believe it depends on where you are in the process as to who decides.
At the initial stage, my understanding is that after you file with your local office, it goes to your state's office. The adjudicator there makes the decision, using doctors imput if necessary. (Like i had to have a mental evaluation because my therapist is not a psychiatrist and the rules demand a doctor's signature on a psych evaluation).
Some states have an appeal step which takes place in the same state office, but with a higher Level 2 Disbility Examiner. Some states have eliminated this step.
Depending on your state, if you are denied at the first level(s), it then goes to a court where a federal judge decides it and that seems to be where it can take months and even years for some. Bah!
Just an aside, my caseworker (adjudicator) also said along the way that she saw no problem with my case and I was approved in 45 days or so. Shw was very helpful in telling me that all my doctors had replied and that the only missing piece was the psych exam that was mandated. She was actually very kind and even said with compassion not to worry about the exam as it was not going to do anything but help me, not hurt me.
Wishing you well