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Research Base

Evidence of Effectiveness

Fourteen randomized experiments or quasi-experiments have been conducted to ascertain the effectiveness of PowerTeaching Math (formerly STAD-Math) in diverse settings and with students of various age groups. The studies are listed in Table 1. These include 4 studies in which students or teachers were randomly assigned to treatments and analysis was at the level of assignment, 7 studies in which teachers or schools were randomly assigned to treatments but analysis was at the student level (randomized quasi-experiments), and three quasi-experimental (matched) comparisons. The average effect size across elementary and secondary studies was +0.47. Among the nine studies that took place in elementary schools, the mean effect size was +0.38.


Table 1: Studies of STAD-Math



Study Sample (students)

Effect Size

Elementary Studies

Conring (2009)

Randomized quasi-experiment

44 elementary


Glassman (1989)

Randomized quasi-experiment

441 elementary


Mevarech (1985)

Randomized experiment

67 elementary


Mevarech (1991)

Randomized experiment

54 elementary


Slavin & Karweit (1985a)

Randomized quasi-experiment

382 elementary


Slavin & Karweit (1985b)

Randomized quasi-experiment

212 elementary


Slavin, Madden, & Leavey (1984)

Randomized quasi-experiment

1,367 elementary


Stevens & Slavin (1995)


873 elementary


Suyanto (1998)


664 elementary


Secondary Studies

Barbato (2000)

Randomized quasi-experiment

208 secondary


Nichols (1996)

Randomized experiment

80 secondary


Reid (1992)


50 secondary


Slavin & Karweit (1984)

Randomized experiment

558 secondary




Measures of Impact on Diverse Populations

The theory of action on the effectiveness of PowerTeaching Math (PTM) is that the cooperative structures create a learning environment in which students support each other’s learning through discussion of challenges and errors, on-the-spot explanations, and motivation to contribute to the success of the team.  This approach utilizes a heterogeneous team structure, and hypothesizes that the opportunities for discussion increase the learning rate of students at a wide range of levels.  The research on cooperative learning supports this hypothesis (Slavin, 2010) as do evaluations of PTM.  Slavin and Karweit (1985) examined the impact of PTM following redistricting for racial integration in a Delaware district.  Students participating in PTM gained a full year more than students in a randomized comparison group.  Gains were equivalent across all racial groups, and for boys and girls.  Students in PTM had greater liking of math and higher self-concept in math, both critical elements for continuation in math coursework and consideration of STEM in college and career choices.


Further evidence of the range of impact was found in a study in rural Maryland. Stevens and Slavin (1995) found that gains for gifted students participating in PTM in a heterogeneous classroom were greater than gains for gifted students participating in special enrichment classes, and gains for special education students in the same PTM classrooms were greater than the gains for special education students instructed using traditional methods.


In a series of studies of diverse populations, Slavin, Madden and Simons (1999) found consistent and substantial gains for cooperative learning on state assessment measures.  In San Antonio, Texas, a school serving primarily economically disadvantaged second language learners almost doubled the percent of students passing the Texas state assessment, moving from 41 to 75 percent passing, which closed the gap between the school and the less disadvantaged schools in the same district.  In Florida, a school serving a highly impoverished African American population (90% of students qualified for free or reduced price lunches) gained 25 percentile points on the Comprehensive Test of Basic Skills, outscoring the districts own math-science-technology magnet school.  In four schools in a very economically deprived rural area in Maryland, students completely closed the gap between their math scores and the state average on the Maryland State Performance Assessment after two years of implementation.


Taken together, these studies confirm the impact of the cooperative learning structures in PTM on math achievement and attitudes for groups typically underrepresented in STEM courses and careers, and provide clear evidence that PTM can be a powerful strategy for increasing interest in and access to STEM.