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.

KEYWORDS:

• Intellectual disability
• quality of life
• validity
• reliability
• Personal Outcomes Scale
• Japan

Acknowledgments

We would like to thank the Department of Sociology, University of Copenhagen. Dr Jørgen Elm Larsen and Dr Myra Lewinter provided insightful feedback and suggestions. We also express our gratitude to the Danish government for the Danish Government Scholarship under the Cultural Agreements, which significantly supported the doctoral study of the first author in Denmark and Japan. Further, we thank Prof. Jos Van Loon of the Department of Special Education at Ghent University, Belgium, and Remco Mostert, BSW of the University College Ghent, for their support and helpful comments on the use of the POS.

Disclosure statement

This study is a revision of the doctoral dissertation of the first author.

Additional information

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Danish Government Scholarship under the Cultural Agreements [grant numbers KULVO-2016-02, KULVO-2017-02]; and the Scandinavia-Japan Sasakawa Foundation [grant number 16-2].