The purpose of this research was to conduct psychometric analysis of a diagnostic assessment instrument, being developed to identify overall levels of developmental delay and characteristics of infants and toddlers. First, the process of test item dev...
The purpose of this research was to conduct psychometric analysis of a diagnostic assessment instrument, being developed to identify overall levels of developmental delay and characteristics of infants and toddlers. First, the process of test item development and the result of content validity are described. Second, results from a sample of 296 children between the ages of 0 and 35 months are presented. Explorations of within-scale relationships yielded evidence of content validity as well as construct validity. The results of test-retest reliability and standard error of measurement demonstrates strong stability. The primary limitation of this study is that infants and toddlers with disabilities are not included in the sample, and the generalization of the results to this population is limited. It is suggested that infants and toddlers with disabilities be included in the future study to develop more valid test items and procedures.