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Analysis: Math gaps between kids start in kindergarten and often persist through Grade 9

One of the most effective ways to narrow achievement gaps and improve long-term educational outcomes could be investing in children’s earliest years, write Erik Duku, Fatemeh Ameli, Magdalena Janus and Scott Davies.

By Fatemeh Ameli, University of Toronto; Eric Duku, McMaster University; Magdalena Janus, University of British Columbia; and Scott Davies, University of Toronto August 7, 2026

A child stacks blocks on a carpet with other children and an educator seen in soft focus in the background.
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)

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Fatemeh Ameli is a lecturer at the Ontario Institute of Studies in Education at the University of Toronto; Eric Duku is an associate professor of Psychiatry & Behavioural Neurosciences at McMaster University; Magdalena Janus is a professor in the Department of Pediatrics at the University of British Columbia; and Scott Davies is a professor at the Ontario Institute for Studies in Education at the University of Toronto. This article is republished from The Conversation under a Creative Commons license. Read the original 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.

Among the different aspects of school readiness, children’s language and cognitive development at kindergarten entry emerged as the strongest and most consistent predictor of later math achievement. Children who entered school less prepared in this area performed substantially worse in Grade 3 math than their peers who were developmentally on track, and this disadvantage persisted into Grade 9.

This pattern is consistent with earlier Ontario research, which found similar links between EDI scores and Grade 3 achievement, as well as a study from British Columbia that linked kindergarten development to well-being and academic scores in middle childhood.

Social competence and physical well-being also predicted later math achievement. In some cases, these factors were as powerful or even more powerful than characteristics such as sex or first language.

In other words, how ready a five-year-old is to engage with learning, follow classroom routines, interact with peers and develop early literacy and numeracy skills tells us a great deal about how they are likely to perform on math assessments years later.

Early inequities persist, but schools still matter

One of our most important findings is that most of the variation in math achievement occurs among individual students rather than among schools or school boards.

Children begin school with different family circumstances, access to early learning opportunities and community supports. These early experiences shape the skills they bring to school, and those initial differences can persist throughout their educational careers.

Policy efforts focused only on under-resourced schools or boards may miss where most of the actual disparity lies. However, this does not mean schools are unimportant. The achievement gaps we observed remained relatively stable over time, suggesting that, at the very least, Ontario schools do not contribute to widening existing inequities.

Why this matters for policy

Educational conversations in Canada tend to focus on interventions during the school years: tutoring, smaller class sizes and curriculum reform. Our findings suggest a complementary, and perhaps more powerful, approach: investing in children’s readiness before they ever walk into a Grade 1 classroom.

Ontario already has a related policy in place. The full-day kindergarten program, introduced more than a decade ago, was designed in part to give all children more structured time to build early skills.

Our results support the logic behind that kind of universal, early investment, rather than waiting to intervene once gaps are already visible on a report card. Research on the EDI across multiple Canadian provinces consistently shows that children’s vulnerability at school entry reflects broader social determinants, which makes universal programs even more important.

Because readiness extends beyond academics, children’s physical well-being and social skills matter too. The most promising interventions are therefore likely to be holistic rather than narrowly academic to address the full range of development that shapes how children arrive at school.

Our findings send a clear message: many achievement gaps begin long before children write their first standardized math test. If Canada wants to narrow achievement gaps and improve long-term educational outcomes, investing in children’s earliest years may be one of the most effective places to start.The Conversation

Fatemeh Ameli is a lecturer at the Ontario Institute of Studies in Education at the University of Toronto; Eric Duku is an associate professor of Psychiatry & Behavioural Neurosciences at McMaster University; Magdalena Janus is a professor in the Department of Pediatrics at the University of British Columbia; and Scott Davies is a professor at the Ontario Institute for Studies in Education at the University of Toronto. This article is republished from The Conversation under a Creative Commons license. Read the original article.

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