Abstract
Background
The Brief Balance Evaluation Systems Test (Brief-BESTest) was recently proposed as a clinical tool for quickly measuring balance disorders, but its measurement properties warrant investigation.
Objective
The study objective was to perform a detailed analysis of the psychometric properties of the Brief-BESTest by means of Classical Test Theory and Rasch analysis.
Design
This was an observational measurement study.
Methods
Brief-BESTest data were collected from a sample of 244 participants. Internal consistency was analyzed with the Cronbach α and item-to-total correlations. Test-retest reliability and interrater reliability were investigated in a subgroup of 21 participants. The minimum detectable change at the 95% confidence level was calculated. Scale dimensionality was examined through Horn parallel analysis; this step was followed by exploratory factor analysis for ordinal data. Finally, data were examined using Rasch analysis (rating scale model).
Results
The Cronbach α was .89, and all item-to-total correlations were greater than .40. Test-retest reliability had an intraclass correlation coefficient (ICC) (2,1) of .94, and interrater reliability had an ICC (2,1) of .90. The minimum detectable change at the 95% confidence level was 4.30 points. The unidimensionality of the test was confirmed, but 1 item showed low communality. Rasch analysis revealed the inadequacy of response categories, 5 misfitting items, minor mistargeting, moderate person reliability (.80), and 2 pairs of locally dependent items.
Limitations
The sample was a cross-section of people who had balance disorders from different neurological etiologies and were recruited consecutively at a single rehabilitation facility.
Conclusions
The Brief-BESTest was confirmed to have some acceptable-to-good reliability indexes when calculated according to Classical Test Theory, but the scale showed fairly limited sensitivity to change. Rasch analysis indicated that item selection should be improved from a psychometric point of view. Item redundancy needs to be reduced, and the metric coverage of the measured construct needs to be improved with new items.
The nutrition for sport knowledge questionnaire (NSKQ): development and validation using classical test theory and Rasch analysis
