Socializing a client to the cognitive behavioural model is advised in almost every cognitive behavioural therapy (CBT) textbook, but there is limited evidence for whether socialization is measurable or important. The aim of the study was to pilot a written and interview-based measure of socialization to investigate whether socialization to the model can be measured in a sample of young people who have completed CBT. Sixteen participants (mean age 14.9 years, 75% female) completed a semi-structured socialization interview and a novel written measure of socialization. Treating clinicians were asked to provide subjective ratings of participant socialization. The structure and content of these measures was examined. A moderate but non-significant correlation was found between the novel written measure of socialization and clinician rating of socialization (r = .37). The concept of ‘socialization’ is not well understood and the socialization interview presented mixed, unclear results. This may be due to issues with the design, but may also be that socialization, as currently understood, is more complex than can be captured in this way. The important aspect of this study is introducing the concept of measuring socialization and factors that may be important in future research. Socialization to the model is an important construct within CBT but at present is a challenging concept to measure. Future research will need to focus on operationalizing the concept further and refining measures so that it can be accurately captured. Understanding which therapist and client behaviours contribute to the process of socialization could conceivably improve outcomes, but this cannot be done until this area is understood more fully.