Determination of validity and reliability of the Bayley scales in infant and toddler development

For diagnosing children who are suspected to have developmental delay through developmental screening tests, we need a valid and reliable diagnostic tool. The Bayley scales is a well-known diagnostic developmental assessment on cognitive, communication and motor domains. The aim of this study was validity and reliability determination of the Bayley test.
The method of this study was descriptive-analytic. The test was provided through translation- back translation and cultural adaptation. Content and face validity of tool was determined by experts’ opinions. 260 children aged 1 to 42 months were recruited for developmental assessment by Bayley. Reliability of test was calculated through three methods; internal consistency, test-retest and inter-rater. Construct validity was calculated using factor analysis and comparison of the mean scores methods.
Participants were 260 children 15 days to 42 months, including 134 boys (51.5%). Cranach’s alpha coefficients were more than 0.76 for all domains. Pearson correlation coefficient in different domains, were at least 0.987 (P These results indicated that the Bayley is a valid and reliable tool for developmental assessment in Persian children.