Developmental patterns in the associations between instructional practices and children's math trajectories in elementary school

•Changes in math instruction are linked to changes in math achievement from K–5.•Developmental patterns found in associations between math instruction & achievement•High amounts of procedural instruction were most beneficial in kindergarten.•High amounts of both conceptual & procedural instruction most effective in 5th grade

Although procedural and conceptual math instruction have been linked to children's math achievement in elementary school, the extant research provides an inconsistent developmental picture of how children respond to a variety of instructional inputs from kindergarten through 5th grade. Using data from a large, longitudinal sample, the ECLS-K (n = ~ 7600), this study considered how within-child changes in exposure to procedural and conceptual approaches are additively and interactively linked to corresponding changes in children's math achievement across elementary school. Specifically, this investigation examined whether these instructional associations with math achievement change as children progress from kindergarten to 5th grade. Significant two- and three-way interactions between instructional approach and longitudinal time were detected. Although an emphasis on procedural instruction was most positively linked to achievement for kindergarteners, a combination of both conceptual and procedural instruction was more beneficial for 5th graders' achievement. Implications for practice are discussed.