Exploring the Accuracy and Consistency of a School Readiness Assessment Tool for Preschoolers: Reliability, Validity and Measurement Invariance Analysis.

This study focuses on examining the psychometric properties of the DIFER test, a widely used assessment tool for measuring school readiness. DIFER, which stands for Diagnostic Assessment Systems for Development, has gained prominence in Hungary and some European countries as an effective means of evaluating children's readiness for school. By investigating the reliability and validity of the DIFER test, this study aims to enhance the understanding of the suitability of the DIFER test for cross-cultural and longitudinal studies in assessing school readiness. Conducted as a survey study, the research involved 3050 Hungarian students from Slovakia and Hungary. Employing Rasch analysis and multi-group confirmatory factor analysis (MG-CFA) aid in verifying the precision of the DIFER test as a valuable assessment instrument for determining school readiness. The results revealed a strong alignment between the difficulty level of the test and students' actual abilities, demonstrating its reliability and validity. Importantly, the analysis found measurement invariance across various factors, including country, gender, and age. This indicates the consistent performance of the DIFER test in assessing school readiness across diverse groups. However, mean differences in latent abilities were observed among different age groups, indicating that older students exhibited notably higher proficiency in pre-mathematical skills compared to their younger counterparts. The findings offer valuable insights to educators, providing a reliable tool for assessing school readiness and identifying areas for improvement.