Background: Although several paper-and-pencil and digital online measures have been developed to assess basic numeracy skills and identify mathematical learning difficulties in children, psychometric evidence of these measures are seldom thoroughly reported and published. Establishing the validity and reliability of educational measures is a fundamental part of evidence-based practice. Objective: This study aimed to examine the test-retest reliability, longitudinal measurement invariance, and convergent validity of a new digital online dyscalculia screener, the Functional Numeracy Assessment Dyscalculia Battery (FUNA-DB), targeted to 9–16-year-old children. Method: The participants were 358 children (165 boys and 193 girls) in grades 3, 5 and 7, who participated in the study at two time points. Children's numeracy skills were measured using two time-limited tests: the FUNA-DB online screener and a standardized paper-and-pencil basic arithmetic test, RMAT. Results: Our results showed that the FUNA-DB has a strong test-retest reliability, displays measurement invariance over time, and is meaningfully related to RMAT. Conclusion: The psychometric evidence supports using the FUNA-DB to measure school-aged children’s number processing and arithmetical fluency across time.

2024