Japanese version of the Personal Outcomes Scale for persons with intellectual disability: Validity and reliability

ABSTRACT Background The Personal Outcomes Scale is a measurement tool to examine quality of life among persons with intellectual disability. This paper addressed the validity and reliability of the Japanese version of the scale using both self-reports and reports of others. Method Data were collected from 128 people with intellectual disability (90 men and 38 women; M age = 37.19 ± 11.90 (range = 19–69) years) and 27 support workers. Reliability was examined by Cronbach's alpha coefficients, inter-respondent reliability coefficients, and test-retest reliability. Validity was examined by construct validity and criteria-related validity. Results Self- and other-reported versions showed adequate internal consistency (α = 0.79); however, some domains had relatively low internal consistency. Validity tests showed weak to moderate correlations between the total score and the domain scores in both versions. Conclusions The scale is reliable overall; however, cultural aspects should be considered to bolster its reliability for practical application.