Math gaps between Ontario kids start in kindergarten — and often persist through Grade 9

Many achievement gaps begin long before children write their first standardized math test. (Piqsels/Id Frela) Math gaps between Ontario kids start in kindergarten — and often persist through Grade 9 Published: August 5, 2026 9.38am EDT Share article Print article When people think about the roots of a child’s struggles in math class, they may picture a tough teacher, a missed unit or a sudden loss of confidence around fractions. Our new study suggests we should be looking much earlier, at kindergarten, or even before. Using linked provincial data from more than 25,000 Ontario children, we tracked students from kindergarten through Grade 9 to see how each child’s “school readiness” — their cognitive, language, social, emotional and physical skills at school entry — related to their math performance nearly a decade later. The results, published in the Canadian Journal of Behavioural Science, show that the children who started behind in kindergarten were, on average, still behind in Grade 9. The gap didn’t necessarily widen, but neither did it close. This matters because math achievement is closely linked to later educational opportunities, participation in STEM fields and labour market success. At a time when provinces across Canada are trying to address post-pandemic learning loss and reduce educational inequities, our findings suggest that efforts to improve educational outcomes must begin in the early years. Our study is among the first in Canada to provide this kind of large-scale longitudinal evidence from Ontario. What we measured, and how In Ontario, approximately every three years, kindergarten teachers complete the Early Development Instrument (EDI) for each child in their classroom. The EDI is a measure of children’s school readiness reflecting their development in five areas: physical health and well-being, social competence, emotional maturity, language and cognitive skills, and communication and general knowledge. We linked these kindergarten profiles to students’ results on standardized provincial math assessments in Grade 3, Grade 6 and Grade 9, along with information on neighbourhood socioeconomic status, sex, English-language fluency and school characteristics. How ready a five-year-old is to engage with learning and develop early literacy and numeracy skills tells us much about how they are likely to perform on math assessments years later. (Yan Krukau/Pexels) Among the different aspects of school readiness, children’s…