Does Fluency Mediate the Relationship Between Working Memory and Math Achievement?

ABSTRACT

Working memory is a robust predictor of children's mathematics achievement, yet the mechanisms underlying this association remain insufficiently understood. Drawing on theoretical accounts, the present study tested whether fluency, both domain‐specific (math) and cross‐domain (reading), mediates the longitudinal relation between working memory and later math performance. Participants were 536 students followed from third through sixth grade. Working memory was assessed in third grade; math and reading fluency were measured repeatedly across fourth and fifth grade; and mathematics achievement was assessed in sixth grade. We found that math fact fluency fully mediated the relation between working memory and later math achievement, eliminating the direct effect of working memory when it was included in the model. There was no effect for reading. These findings clarify how working memory contributes to mathematical development by highlighting domain‐specific math fluency as a key longitudinal pathway linking working memory to later mathematics achievement.