Assessing stable validity and reliability of the Japanese version of the individualized supported employment fidelity scale: A replication

Background The Japanese version of the individualized Supported Employment Fidelity scale (JiSEF) was developed by modifying the 25-item Individual Placement and Support Fidelity Scale (IPS-25). While a preliminary study partly confirmed the concurrent validity with vocational outcomes, this replication study aimed to examine the stability of the concurrent validity and the inter-rater reliability of the JiSEF and to test its convergent validity with IPS-25. Methods Fidelity assessments were conducted in 2016 (n = 17), 2017 (n = 13), and 2018 (n = 18) to examine the employment rate and the fidelity scores at the agency level. We also evaluated the fidelity scores for the IPS-25 in 2018. We examined the associations between the fidelity scale scores and vocational outcomes for the concurrent validity and between the fidelity scales for convergent validity. The inter-rater reliability was examined in the 2016 and 2017 assessments. Results High intraclass correlation coefficients (0.93 in 2016 and 0.92 in 2017) were obtained for the inter-rater reliability. The JiSEF score in each year was associated with the agency employment rate (r = 0.710, P = 0.001 in 2016; r = 0.722, P = 0.005 in 2017; and r = 0.665, P = 0.003 in 2018). A supplementary longitudinal data analysis also confirmed the association between the JiSEF score and the employment outcomes. Additionally, the JiSEF was significantly correlated with the IPS-25 (r = 0.760, P < 0.001). Conclusions This study stably replicated good inter-rater reliability and concurrent validity of the JiSEF. Additionally, the convergent validity was confirmed. Further studies with large samples are needed to confirm these findings.