In their review, Ablon, Levy, and Smith-Hansen (2011) showed that the Psychotherapy Process Q-set (PQS; Jones, 2000) has been applied to a large range of studies with different methods and aims, from Randomized Control Trials (RCT) to naturalistic studies and single-case designs. Focusing on our colleagues’ work, we will highlight the contribution of the PQS to research in psychotherapy, not only in process-outcome studies, but also into the therapeutic action debates, the specific vs common factors discussion, and the insight vs relation dialect. According to our studies, PQS has played the most relevant and innovative role in psychoanalysis. Ablon et al. (2011) showed how Jones left the clinical inheritance of his empirical method. One of PQS’s strengths deals with the Q-sort methodology (Stephenson, 1953; Block, 1961) that enables both an empirical study of human subjectivity (McKnown & Thomas, 1988) and the application of rigorous data analysis for single-case designs, such as the P-technique and time series analysis. PQS, as colleagues have shown, is useful in single-case designs that, despite their limitations in the generalization of the findings (Kazdin, 2002), capture the richness and complexity of the clinical dialogue and describe the uniqueness of the patient and therapist dyad and interaction structures.
PQS, research on psychotherapy process