Six senior clinicians studied transcripts of randomly selected psychotherapy hours, focusing on the effect that interventions by the therapist had on the patient's ability to collaborate in the treatment. The researchers modified or constructed several clinically oriented scales for use in the work. One measure of collaboration was Lester Luborsky's therapeutic alliance scales, which reflect a global assessment of an entire session. The other measures, which were intended to identify changes within sessions, dealt with 50-line segments of transcripts, with thirds of sessions, and with collaboration across an entire session.