Understanding the Dynamics of Dosage Response: A Nonlinear Meta-Analysis of Recent Reading Interventions

Garrett J. Roberts, Denis G. Dumas, Daniel McNeish, Brooke Coté

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Researchers have noted a nonlinear association between reading instruction dosage (i.e., hours of instruction) and reading outcomes for Grade K–3 students with reading difficulties (K–3 SWRD). In this article, we propose a nonlinear meta-analysis as a method to identify both the maximum effect size and optimal dosage of reading interventions for K–3 SWRD using 26 peer-reviewed studies including 186 effect sizes. Results suggested the effect sizes followed a concave parabolic shape, such that increasing dosage improved intervention effects until 39.92 hours of instruction (dmax = 0.77), after which the intervention effects declined. Moderator analyses found that maximum intervention effects on fluency outcomes were significantly larger (dmax = 1.34) than the overall maximum effect size. Also, when students received 1:1 instruction, the dosage response curve displayed a different functional form than the concave parabolic shape, showing the effect increased indefinitely after approximately 16.8 hours of instruction. Implications for research and practice are discussed.

Original languageEnglish (US)
Pages (from-to)209-248
Number of pages40
JournalReview of Educational Research
Issue number2
StatePublished - Apr 2022


  • elementary
  • meta-analysis
  • reading disability
  • reading intervention

ASJC Scopus subject areas

  • Education


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