Reliability of the Gait Outcomes Assessment List questionnaire.

AIM

To report the test-retest reliability of the parent version of the Gait Outcomes Assessment List (GOAL) questionnaire for item, domain, total score, and goal importance in children with cerebral palsy (CP) functioning in Gross Motor Function Classification System (GMFCS) levels I to III.

METHOD

The GOAL questionnaire was completed twice, 3 to 31 days apart, in a prospective cohort study of 112 caregivers of children aged 4 to 17 years with CP (40% unilateral; GMFCS level I = 53; II = 35; III = 24; 76 males). All had an outpatient visit over a 1-year period. The standard error of measurement (SEM), minimum detectable change, and agreement were calculated for all responses, including goal importance.

RESULTS

The SEM for the total score was 3.1 points for the cohort (GMFCS level I = 2.3, GMFCS level II = 3.8, GMFCS level III = 3.6). The standardized domain and item scores were less reliable than the total score and varied according to GMFCS level. The gait function and mobility domain exhibited the best reliability for the cohort (SEM = 4.4), whereas the use of braces and mobility aids domain exhibited the lowest (SEM = 11.9). Goal importance was reliable (cohort average agreement 73%).

INTERPRETATION

The parent version of GOAL has acceptable levels of test-retest reliability for most domains and items. Caution is advised when interpreting the least reliable scores. Essential information necessary for accurate interpretation is provided.

WHAT THIS PAPER ADDS

The standard error of measurement (SEM) of the Gait Outcomes Assessment List (GOAL) total score was approximately 3 points. The SEM of the GOAL domain score ranged from 4 to 12 points. The use of braces and mobility aids domain had the lowest reliability score. Item-level reliability varied according to domain and Gross Motor Function Classification System level. Caregivers reliably identified item importance with approximately 73% agreement.