New Analysis Finds Two Measures Boost K-12 Academic Achievement

Ability Grouping
Tuesday, December 6, 2016

FOR IMMEDIATE RELEASE: Tuesday, Dec. 6, 2016

Katy Munger (Duke TIP)
(919) 668-9153


DURHAM, N.C. -- A new, comprehensive analysis of a century’s worth of research shows that grouping students by ability and providing opportunities for students to progress at a more rapid pace can increase overall student academic achievement.

The study was conducted by researchers at the Duke University Talent Identification Program (Duke TIP) and Northwestern University.

This latest study examined the equivalent of nearly 300 original research studies and found that both educational techniques work.

“After looking carefully at 100 years of research, it became clear that acceleration and most forms of ability grouping can be powerfully effective interventions,” said study co-author Matt Makel, research director at Duke TIP. “They help increase academic achievement for both lower- and higher-achieving students. 

“Moreover, these practices can yield significant academic benefits without being expensive and can even save schools money.”   

Makel said it is important to remember that “individual differences matter. We need to be constantly responsive to student learning needs.”

Given that the U.S. spends nearly $600 billion a year on public K-12 education, the study’s results could help policymakers improve the nation’s struggling school systems, Makel said.


Using a technique called second-order meta-analysis, the study’s authors collated and examined 13 previously published research studies that had, in and of themselves, already synthesized 172 unique studies on the effectiveness of ability grouping. The authors also examined six previously published research studies that had collectively investigated at least 125 unique studies on acceleration techniques. Researchers imposed strict criteria to ensure that best research practices were followed.

This new analysis found that students benefited from both within-class and cross-grade subject grouping, and that gifted students benefited from being placed in special groups or programs specifically designed to serve them. However, evidence also suggested that between-class grouping (putting high-ability students in their own classes and low-ability students in their own classes) without changing the actual curriculum did not change academic achievement.

The analysis that focused on academic acceleration (e.g., grade skipping, early entrance to school, etc.) suggested a positive impact on the academic achievement of students compared to similar-age students who had not been accelerated. It also showed that accelerated students performed no differently than the older non-accelerated students with whom they had been grouped.

This latest study highlights the gap between empirical support for ability grouping and acceleration and the lack of policy support for implementing these techniques in schools, Makel said.

With a century of research showing the effectiveness of most types of ability grouping and acceleration, the question of why these techniques are not more universally implemented looms large for educators, parents, and lawmakers, Makel said, especially given that policymakers are constantly searching for educational interventions that are effective and can be implemented on a large scale for relatively low cost.

The study, “What One Hundred Years of Research Says about the Effects of Ability Grouping and Acceleration on K–12 Students’ Academic Achievement: Findings of Two Second-Order Meta-Analyses,” is co-authored by Saiying Steenbergen-Hu and Paula Olszewski-Kubilius of Northwestern University’s Center for Talent Development (CTD).

View the study in its entirety at the Review of Educational Research (subscription required); download a summary of the study here (PDF); or contact Duke TIP’s Director of Research Matt Makel or Saiying Steenbergen-Hu of Northwestern University’s CTD to obtain the full article or discuss the study’s methods and conclusions in more detail.


About Duke TIPDuke University Talent Identification Program (Duke TIP) is a nonprofit organization dedicated to serving academically talented youth. Duke TIP works with students, families and educators to identify, recognize, challenge, engage and support gifted youth in reaching their highest potential. More than 2.8 million students have benefited from TIP programs and resources since 1980, and its talent identification, academic and research programs now serve as models for the education of gifted students.

About CTD: The Center for Talent Development (CTD) at Northwestern University is dedicated to helping gifted and talented students, age 4 through grade 12, reach full potential. They provide research-based assessment, advanced academic programs, and resources to enhance gifted education. Since 1982, CTD has evolved from a single focus on talent identification to a multi-faceted operation with four central goals: talent identification, talent development, research and advocacy.