Test of gross motor development-2 for Filipino children with intellectual disability: validity and reliability

Abstract

This study aimed to examine aspects of validity and reliability of the Test of Gross Motor Development-2 (TGMD-2) in Filipino children with intellectual disability. Content and construct validity were verified, as well as inter-rater and intra-rater reliability. Two paediatric physiotherapists tested 81 children with intellectual disability (mean age = 9.29 ± 2.71 years) on locomotor and object control skills. Analysis of covariance, confirmatory factor analysis and analysis of variance were used to test validity, while Cronbach’s alpha, intra-class correlation coefficients (ICC) and Bland–Altman plots were used to examine reliability. Age was a significant predictor of locomotor and object control scores (P = 0.004). The data fit the hypothesised two-factor model with fit indices as follows: χ² = 33.525, DF = 34, P = 0.491, χ²/DF = 0.986. As hypothesised, gender was a significant predictor for object control skills (P = 0.038). Participants’ mean scores were significantly below mastery (locomotor, P < 0.001; object control, P < 0.001). Cronbach’s alpha was 0.830 for locomotor and 0.792 for object control components. ICC for locomotor and object control scores ranged from 0.995 to 0.998, suggesting excellent intra-rater and inter-rater reliability, confirmed by Bland–Altman analysis. This study provides evidence of sufficient content and construct validity, internal consistency and rater reliability of TGMD-2 for Filipino children with intellectual disability.

Keywords:

• child
• locomotor
• object control
• intellectual disability
• developing country

Additional information

Funding

This study was supported in part by the Marden Seed Funding grant of the Centre for Advancement of Inclusive and Special Education, the University of Hong Kong. The second author was supported by an Erasmus Mundus scholarship of the European Commission at the University of Leuven, Belgium.