Performance on curriculum-based mathematics assessments in developmental dyscalculia: the effect of content domain and question format.

Developmental Dyscalculia (DD) is characterised by persistent difficulties in learning mathematical skills, which usually becomes apparent in the early years of schooling. Traditionally, DD is known to affect children's arithmetic processing, whilst other domains of mathematics receive much less research attention. Nevertheless, contemporary diagnostic guidelines suggest that DD is linked to widespread and diverse difficulties, both within and outside of the domain of numbers. This study examined the performance (i.e., accuracy and number of questions attempted) of children on a curriculum-based mathematics assessment, considering the effect of content domains, question format (i.e., multiple-choice questions vs. constructed response questions) and test half. Participants were forty children aged 8 to 11 years old with DD (n = 20) and a carefully matched control group of typically developing children (n = 20) from primary schools in Northern Ireland. Results revealed that the DD group achieved significantly lower scores than the control group across all areas of the curriculum, and the magnitude of group differences was similar across all content domains. These findings indicate that performance in content domains other than in arithmetic may be equally informative in supporting the identification of children with DD. In addition, we found that using multiple-choice questions may support learners with DD in achieving the best outcome, and, thus, could be useful for assessing mathematics skills in dyscalculic children in classroom contexts. Nevertheless, constructed response questions may show the greatest sensitivity to identifying learners at risk, and could be the most useful in diagnostic settings.