Validity and reliability of the Japanese version of the Therapeutic Factors Inventory-19: A study of family peer education self-help groups

Aim: Therapeutic factors are crucial mechanisms that promote change in self-help group members. Measuring therapeutic factors may improve practitioners' skills for assessment in whole-group contexts. The present authors, therefore, examined the validity and reliability of a Japanese version of the Therapeutic Factors Inventory-19.

Methods: The Therapeutic Factors Inventory-19 was examined using a self-report questionnaire completed by members of 38 family peer education self-help groups. The instrument measured the following four factors: instillation of hope, secure emotional expression, awareness of relational impact, and social learning.

Results: Participants were 246 group members. Test-retest reliability was analyzed using data from 46 participants. Confirmatory factor analysis showed a goodness of fit of 0.85 and a root mean square error of approximation of 0.088. Multitrait scaling analyses showed that items for instillation of hope and secure emotional expression factors correlated higher with their own factors than other factors. Each factor and the total average of the 19 items were significantly correlated with the Group Benefit Scale and Client Satisfaction Questionnaire. When level of interaction with other members was higher, subjects perceived a stronger presence of therapeutic factors. The intraclass correlation coefficients of each factor at a week interval were 0.848-0.915. Cronbach's alpha of each factor and all items ranged 0.767-0.960.

Conclusion: In the case of family peer education self-help groups, there is acceptable validity and reliability for the average score of all items, and for the instillation of hope and secure emotional expression factors. However, more work is needed to increase the generalizability.