Classifications of psychotherapy procedures have not yet reached unanimous consent, as the wide range of theoretical terms used in the definitions produce linguistic barriers. The CLP project may change this by defining over 100 psychotherapy procedures clearly and operationally in plain language with minimal or no use of theoretical terms. Marks et al.(2012) first tried to lower the barriers by empirically classifying psychotherapy procedures using their features (“domains”, Classification “A”). However, observers are not passive recorders and classification involves choices, so observer bias can’t be totally excluded, especially if choices are not explicit a priori. We therefore decided that the first two Authors (also members of the Project Task Force) would make a second classification (“B”) independently in order to compare Classifications A with B at a second stage.

Method: The same set of procedures as in Marks et al.(2012) was classified independently, but with different assumptions, using a definition of psychotherapy procedure which differentiates its therapeutic goal (s) from its components. The goal was defined as the psychological dimension which the procedure aims to modify (usually stated in the CLP definition), while the components are the steps taken to this end, inferred from the procedure’s description and brief case illustration. The goal areas agreed a priori between the two Authors (S. Borgo & L. Sibilia) were chosen according to the main psychological response systems: cognitive, behavioral, emotional (affective) and somatic (sensations). Then the two raters (SB & LS) allocated independently the goals of each procedure to one of the four goal areas. The concordance rates were computed with a Chi Square analysis.

Results: Concordance was significantly better than chance for all 4 areas, the overall rate of agreement being 78%. 15 components were found in Classification B, which were also independently classified by the two raters; overall 85% of all procedures were classified.

Conclusion: Defining psychotherapy procedures in plain language with operational descriptions led raters to agree fairly well in classifying psychotherapy procedures, and to the identification of less than 20 procedural components in psychotherapies across orientations.