What's the difference btw. an accepted psychotherapy technique and a technique that produces a placebo effect?

Question

How can we determine if the outcome is caused by the person's belief and not on the technique?

Answer 1

With an accepted psychotherapy technique, there is evidence which supports a direct link to the methods employed and the outcome.  So, for example, systematic desensitization has been shown to have direct benefit in treating phobias.

A placebo effect suggest a positive benefit that is not directly linked to the methods employed.  A placebo is more dependant on the individual's hope or expectation that a treatment is going to have benefit rather than the specific technique employed.