University of Oulu

Ikonen, J., Hulkkonen, S., Ryhänen, J., Häkkinen, A., Karppinen, J., & Repo, J. (2020). The structural validity of the Finnish version of the Disabilities of the Arm, Shoulder and Hand: A Rasch model analysis. Hand Therapy, 25(1), 3–10.

The structural validity of the Finnish version of the Disabilities of the Arm, Shoulder and Hand : a Rasch model analysis

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Author: Ikonen, J1,2; Hulkkonen, S3; Ryhänen, J3;
Organizations: 1Department of Surgery, Central Hospital of Central Finland, Jyväskylä, Finland
2Department of Hand Surgery, Turku University Hospital and University of Turku, Turku, Finland
3Department of Hand Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
4Faculty of Sports and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
5Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland
6Finnish Institute of Occupational Health, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.3 MB)
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Language: English
Published: SAGE Publications, 2020
Publish Date: 2020-12-10


Introduction: The construct validity of the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH) has previously been questioned. The purpose of this study was to evaluate the measurement properties of the Finnish version of the DASH for assessing disability in patients with hand complaints using Rasch Measurement Theory.

Methods: A cohort of 193 patients with typical hand and wrist complaints were recruited at a surgery outpatient clinic. The DASH scores were analysed using the Rasch model for differential item functioning, unidimensionality, fit statistics, item residual correlation, coverage/targeting and reliability.

Results: In the original DASH questionnaire, the item response thresholds were disordered for 2 of 30 of the items. The item fit was poor for 9 of 30 of the items. Unidimensionality was not supported. There was substantial residual correlation between 87 pairs of items. Item reduction (chi square 95, degrees of freedom 50, p < 0.001) and constructing two testlets led to unidimensionality (chi square 0.64, degrees of freedom 4, p = 0.96). Person separation index was 0.95. The testlets had good fit with no differential item functioning towards age or gender.

Conclusion: Unidimensionality of the original Finnish version of the DASH was not supported, meaning the questionnaire seems to gauge traits other than disability alone. Hence, the clinician must be careful when trying to measure change in patients’ scores. Item reduction or the creation of testlets did not lead to good alternatives for the original Finnish DASH. Differential item functioning showed that the original Finnish scale exhibits minor response bias by age in one item. The original Finnish DASH covers different levels of ability well among typical hand surgery patients.

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Series: Hand therapy
ISSN: 1758-9983
ISSN-E: 1758-9991
ISSN-L: 1758-9983
Volume: 25
Issue: 1
Pages: 3 - 10
DOI: 10.1177/1758998320907116
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
Copyright information: © 2020 SAGE Publications. The final authenticated version is available online at