Reliability of the performance and safety scores of the wheelchair skills test version 4.1 for manual wheelchair users

Abstract

Objective: To evaluate the interrater, intrarater, and test-retest reliability of the total performance and safety scores of the Wheelchair Skills Test version 4.1 (WST 4.1) for manual wheelchairs operated by adult wheelchair users.

Design: Cohort study.

Setting: University research setting.

Participants: People (N=11) who used manual wheelchairs for community locomotion.

Interventions: Not applicable.

Main outcome measure: Participants were videotaped as they completed the WST 4.1 (30 skills) on 2 separate occasions 1 to 2 weeks apart. Subsequently, raters scored the WST 4.1 from the video recordings and each participant received a total score for performance and safety. Using those scores, interrater, intrarater, and test-retest reliability were determined by using intraclass correlation coefficients (ICCs). Percentages of agreement between raters for individual skills also were calculated.

Results: Mean ± SD overall WST 4.1 scores for performance and safety were 80.1%±8.5% and 98.0%±2.8%. ICCs for the interrater, intrarater, and test-retest reliability of the performance component were .855, .950, and .901 (P<.001). Safety component ICC scores were .061 (P=.243), .228 (P=.048), and .254 (P=.041). Percentages of agreement between raters for each test item for both the performance and safety scales ranged from 68% to 100%.

Conclusions: Reliability of the performance component of the WST 4.1 was excellent, whereas ICCs for the safety component indicated only slight to fair agreement, probably because of the low variability in safety scores. Additional study is needed to further evaluate the reliability of the safety component with a larger and more diverse sample group.