The Impacts of Success for All on Reading Achievement in Grades 3–5: Does Intervening During the Later Elementary Grades Produce the Same Benefits as Intervening Early?

We evaluate the impact of Success for All literacy instruction in grades 3 through 5 using data from the same cluster randomized trial used to evaluate effects in the earlier grades (K–2). In contrast to the early benefits, there is no effect on reading achievement in the later grades, either overall or for students and schools with high or low baseline reading achievement. This suggests that the impact of Success for All—including established long-term positive effects—may depend on early exposure. As a result, educators may experience difficulty replicating the typical positive achievement impacts of the intervention when children participate in Success for All only during the later elementary grades, as is common for mobile students in program schools