The best outcome studies for evaluating the effectiveness of psychotherapy typically rely on:

The best outcome studies for evaluating the effectiveness of psychotherapy typically rely on randomized clinical trials.
These clinical trials which have been randomly chosen may be the most important and relevant sources when it comes to studies revolving around the effectiveness of psychotherapy, because they clearly show whether or not psychotherapy is effective.

Iam a german monk and professor of theology. i believe that the catholic church's practice of buying forgiveness of sins through indulgences is wrong. i have translated the bible into german to make it easier for more people to be able to study it. i am here to stand by my writings and i refuse your demand that i recant them