A bottom-up approach to assess verbal therapeutic techniques. Development of the Psychodynamic Interventions List (PIL).

Objective: Knowing which specific verbal techniques "good" therapists use in their daily work is important for training and evaluation purposes. In order to systematize what is being practiced in the field, our aim was to empirically identify verbal techniques applied in psychodynamic sessions and to differentiate them according to their basic semantic features using a bottom-up, qualitative approach.

Method: Mixed-Method-Design: In a comprehensive qualitative study, types of techniques were identified at the level of utterances based on transcribed psychodynamic therapy sessions using Qualitative Content Analysis (4211 utterances). The definitions of the identified categories were successively refined and modified until saturation was achieved. In a subsequent quantitative study, inter-rater reliability was assessed both at the level of utterances (n = 8717) and at the session level (n = 38). The convergent validity of the categories was investigated by analyzing associations with the Interpretive and Supportive Technique Scale (ISTS).

Results: The inductive approach resulted in a classification system with 37 categories (Psychodynamic Interventions List, PIL). According to their semantic content, the categories can be allocated to three dimensions: form (24 categories), thematic content (9) and temporal focus (4). Most categories showed good or excellent inter-rater reliability and expected associations with the ISTS were predominantly confirmed. The rare use of the residual category "Other" suggests that the identified categories might comprehensively describe the breadth of applied techniques.

Conclusions: The atheoretical orientation and the clear focus on overt linguistic features should enable the PIL to be used without intensive training or prior theoretical knowledge. The PIL can be used to investigate the links between verbal techniques derived from practice and micro-outcomes (at the session level) as well as the overall therapeutic outcomes. This approach might enable us to determine to what extent the outcome of therapy is due to unintended or non-theoretically relevant techniques.