Factors influencing the impact of math interventions in K-12 education

By Marta Pellegrini, University of Cagliari, Italy

It is commonly understood that educational interventions are not universally effective; their impact varies depending on specific contexts and conditions. A systematic review with meta-analysis by Megan Rojo and her colleagues examined the influence of intervention and study characteristics in determining the effects of K-12 programs for students with mathematical difficulties. They focused on grade level, group size, content area, and dosage for the intervention characteristics; and on research design, implementation fidelity, year of study, type of measure, and study quality for study characteristics.

The review included 286 studies, 119 of which were randomized trials, 16 quasi-experiments, and 86 single-subject designs. In the model excluding extreme values, the authors found the following findings for intervention characteristics.

• Problem-solving interventions and interventions involving operations were found to be less effective than those focusing on fractions. The authors suggested the complex nature of fractions and the specialized knowledge of research teams dedicated to this specific area as potential explanations.
• No clear pattern was found for duration. Longer interventions (more than 22 hours) seemed to have a larger impact, but further research is needed.
• Grade level (K–2 vs. 3–5, vs. 6–12) was not found to influence the impact of the interventions.
• Similar effects were observed in interventions delivered either in small groups or individually, which supports findings from previous reviews.

Study characteristics were considered by the authors because the way the studies were designed and conducted may affect their effect sizes (read related BEiB summaries on this topic here and here). They found that single-subject designs had larger effects compared to quasi-experimental and randomized studies. Measures created by the researchers produced larger effects than independent measures. They concluded that those features should be addressed in future research.