Psychometric testing of the Icelandic Occupational Self-Assessment (OSA-IS)

Abstract

Background

The Occupational Self-Assessment (OSA) is a self-report measure of occupational competence and values used to identify goals and assess outcomes. The Icelandic version of the OSA (OSA-IS) has been through several developmental stages to evaluate its psychometric properties. Through each stage, revisions have been made.

Aim

To investigate the psychometric properties of the fourth revised version of OSA-IS.

Materials and methods

Retrospective data from 291 rehabilitation clients with a range of conditions were analysed using Rasch analysis of unidimensionality and descriptive statistics. All statistics were compared to established criteria.

Results

Analyses suggest the OSA-IS items define unidimensional constructs of occupational competence and values. Most (89%) participants completed the assessment in a reliable manner and no association was observed between demographic variables and fit status. Differences in the item hierarchies were observed between the original OSA and the OSA-IS, suggesting that Icelandic clients responded differently due to cultural, linguistic and/or sample differences.

Conclusion and significance

OSA-IS is a psychometrically sound instrument that may be used to support identification of client-centred goals and for intervention development. Clinicians should use score tables specifically developed for the OSA-IS to measure outcomes.

Keywords:

• Model of human occupation
• occupational competence
• occupational therapy
• occupational values
• patient-reported outcome
• Rasch measurement model
• translation and cultural adaptation

Acknowledgements

The authors would like to thank all the participants in this study, clients, and occupational therapists. Special thanks to Gudrun Palmadottir professor emerita at the University of Akureyri, and to Sigridur Jonsdottir occupational therapist at Reykjalundur Rehabilitation Centre for their part in the translation process, and to Dr. Jessica M. Kramer, University of Florida for her excellent guidance with the Rasch analysis and feedback on numerous drafts of this paper.

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.