Construct Validity and Reliability of the Comprehensive Occupational Therapy Evaluation Scale (COTES) in People With Schizophrenia

En-Chi Chiu; Kuan-Yu Lai; Shih-Ku Lin; Shih-Fen Tang; Shu-Chun Lee; Ching-Lin Hsieh

doi:10.5014/ajot.2019.026807

Construct Validity and Reliability of the Comprehensive Occupational Therapy Evaluation Scale (COTES) in People With Schizophrenia

Am J Occup Ther. 2019 Nov/Dec;73(6):7306205060p1-7306205060p8. doi: 10.5014/ajot.2019.026807.

Authors

En-Chi Chiu¹, Kuan-Yu Lai², Shih-Ku Lin³, Shih-Fen Tang⁴, Shu-Chun Lee⁵, Ching-Lin Hsieh⁶

Affiliations

¹ En-Chi Chiu, OTD, PhD, is Associate Professor, Department of Long-Term Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
² Kuan-Yu Lai, MS, is Occupational Therapist, Department of Occupational Therapy, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan.
³ Shih-Ku Lin, MD, is Psychiatrist, Department of Psychiatry, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan.
⁴ Shih-Fen Tang, MS, is Occupational Therapist, Department of Occupational Therapy, Taoyuan Psychiatric Center, Ministry of Health and Welfare, Taoyuan, Taiwan.
⁵ Shu-Chun Lee, MS, is Doctoral Candidate, School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, and Occupational Therapist, Department of Occupational Therapy, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan; A1057@tpech.gov.tw.
⁶ Ching-Lin Hsieh, PhD, is Professor, School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, and Adjunct Professor, Department of Occupational Therapy, College of Medical and Health Science, Asia University, Taichung, Taiwan.

PMID: 31891345
DOI: 10.5014/ajot.2019.026807

Abstract

Objective: We evaluated the construct validity (i.e., unidimensionality and convergent validity) and Rasch reliability of the 20-item Comprehensive Occupational Therapy Evaluation Scale (COTES) in people with schizophrenia.

Method: Retrospective chart review was used to collect COTES data from 505 inpatients with schizophrenia. For construct validity, we first examined unidimensionality of each of the three COTES subscales using Rasch analysis. After unidimensionality was supported, we examined convergent validity using Pearson's r and Rasch reliability of the individual subscales.

Results: After deleting two misfitting items, the remaining items (i.e., the COTES-18) showed unidimensionality. Infit and outfit mean squares were 0.73-1.25. Moderate correlations were found among the three COTES-18 subscales (rs = .57-.71). The Rasch reliabilities of the three subscales were .83-.92.

Conclusion: The COTES-18 has sufficient construct validity and reliability to assess three specific dimensions of behavior affecting occupational performance in people with schizophrenia.

MeSH terms

Humans
Occupational Therapy / standards*
Psychometrics / methods*
Reproducibility of Results
Retrospective Studies
Schizophrenia / diagnosis*
Surveys and Questionnaires / standards*