Evaluation of the Psychometric Properties of the Test of Gross Motor Development—Third Edition

TLDR

Recent revisions necessitate evaluating the reliability and validity of the Test of Gross Motor Development—3rd edition (TGMD‑3). The TGMD‑3 was administered to 807 children (mean age 6.33 ± 2.09 years, 52.5 % male). The TGMD‑3 demonstrated moderate‑to‑large age correlations (r = .39–.47), very high internal consistency across age, race/ethnicity, and sex, excellent test‑retest ICCs (0.95–0.97), acceptable item difficulty (0.43–0.91) and discrimination (0.34–0.67), a one‑factor structure explaining 73.82 % of variance, and acceptable CFA fit (χ²(65)=327.61, p<.001, CFI = .95, TLI = .94, RMSEA = .10), confirming high validity and reliability.

Abstract

With recent revisions, the evaluation of the reliability and validity of the Test of Gross Motor Development—3rd edition (TGMD-3) is necessary. The TGMD-3 was administered to 807 children ( M age = 6.33 ± 2.09 years; 52.5% male). Reliability assessments found that correlations with age were moderate to large; ball skills had a higher correlation ( r = .47) compared with locomotor skills ( r = .39). Internal consistency was very high in each age group and remained excellent for all racial/ethnic groups and both sexes. Test-retest reliability had high ICC agreements for the locomotor (ICC = 0.97), ball skills (ICC = 0.95), and total TGMD-3 (ICC = 0.97). For validity measures, the TGMD-3 had above acceptable item difficulty (range = 0.43–0.91) and item discrimination values (range = 0.34–0.67). EFA supported a one-factor structure of gross motor skill competence for the TGMD-3 with 73.82% variance explained. CFA supported the one-factor model (χ 2 (65) = 327.61, p &lt; .001, CFI = .95, TLI = .94, RMSEA = .10), showing acceptable construct validity for the TGMD-3. Preliminary results show the TGMD-3 exhibits high levels of validity and reliability, providing confidence for the usage and collection of new norms.