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Dr. Spencer Kagan

Effect Size Reveals the Impact of Kagan Structures and Cooperative Learning

Special Article

Cooperative Learning and Kagan Structures Boost Achievement in Many Ways

Over 1000 research studies have documented cooperative learning's powerful positive effects on a wide range of variables including:

•Increased Achievement Across All Grades and Subjects
including Physical Education Skills
• Increased Time on Task
• Improved Ethnic and Race Relations
• Increased Self-Esteem
• Improved Academic and Social Outcomes for Students with Special Needs
• Improved Attitudes Toward Students with Special Needs
• Enhanced Thinking Skills
• Increased Social Skills
• Improved Attitude Toward Academic Subject Areas
•Improved Classroom Climate
•Liking of School, class, and teacher

Many of these positive outcomes have been extensively researched and documented.25 Further, informal observations and teacher comments indicate a host of additional benefits. For example, every year at our annual Kagan Summer Academy I have teachers come to me and thank me with comments like, "I used to be looking forward to retirement, but now I am looking forward to next year's school year." "My students really have bonded as a class; they support each other." "I know my students so much better now; we are on the same side."

"I used to be looking forward to retirement, but now I am looking forward to next year's school year."

That cooperative learning has so many positive outcomes is a practitioner's dream, but a researcher's nightmare. It is almost impossible to tease out exactly why cooperative learning produces achievement gains or how much each of these variables contribute to the positive impact of cooperative learning on achievement. Let's take three of many possible examples that illustrate that cooperative learning impacts different variables that in turn impact on achievement: feedback, discipline, and teacher-student relations.

Feedback and Formative Evaluation. When students do a cooperative learning structure like Sage-N-Scribe or RallyCoach, they receive feedback following each problem they solve, not after each worksheet. Further, they receive the feedback immediately, rather than after the teacher has had time to grade their worksheets. This is formative feedback as it is received prior to the test — it allows students to improve as they practice rather than getting feedback following practice. Frequency and immediacy of feedback are increased tremendously. Feedback has an extremely high effect size on academic achievement (.73)26 and formative evaluation has one of the highest effect sizes on academic achievement of all educational variables ever studied (.90)!27 The question becomes, how much of the gains produced by cooperative learning are a result of the increase in frequency and immediacy of formative feedback? Another important question is whether Kagan Structures are more effective than other cooperative learning methods because Kagan Structures place a very heavy emphasis on frequent, immediate feedback — far more than do other approaches to cooperative learning? Although these are worthwhile questions to ask, there are a host of other variables cooperative learning impacts, so analyzing the contribution of just feedback will give us but a partial answer.

Discipline. Decreasing disruptive behavior frees teachers to teach and so has a positive effect size on achievement, although not as high as feedback, .34.28 Kagan Structures produce a dramatic reduction of disruptive behavior.29  See Graph: Behavior Incidents 2003-2008. When Kagan Cooperative Learning was implemented in the Spring of 2004 at Mills Hill School in the UK, the school experienced an extraordinary drop in disruptive behaviors. The question becomes, how much does the decrease in discipline problems produced by cooperative learning account for achievement gains it produces?

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Teacher-Student Relations. Teacher-student relations are improved by Kagan Sturucrures. The Kagan approach emphasizes teambuilding and classbuilding through which teachers get to relate to students as indivdiuals, not just as students. Teachers report having increased "contact" with their students and that students much more often confide in them about personal concerns. Teachers are seen as "on the same side" with students, not just as an evaluator.

Teacher Subject Matter Knowledge has an effect size of a mere .09 whereas Teacher-Student Relationships has an effect size of a whopping .72!30 These dramatic effect size differences corroborate the educational aphorism: "They don't care what you know until they know that you care." It is teacher-student relationships, not teacher subject matter knowledge, that cooperative learning impacts. When cooperative learning is implemented, the teacher does not necessarily improve in content knowledge, but definitely improves in student relations. Students like their class, their content, and their teacher more because the teacher moves from being a "sage-on-the-stage" to becoming a "guide-on-the-side." Again, the question becomes how much of the achievement gains of cooperative learning are attributable to improved teacher-student relations?

We could continue detailing a host of variables influenced by cooperative learning, which in turn increase student achievement. Cooperative learning has a positive impact on many mediating variables that have proven strong, positive effects on achievement, including peer tutoring, classroom cohesion, and small group learning. See Table: "Cooperative Learning Boost Achievement via Mediating Variables." There is empirical and informal observation data showing cooperative learning improves each of the variables in the table.31 How much each of these variables explains the positive impact of cooperative learning on achievement is yet to be established. A great deal could be written about how cooperative learning impacts on each of these variables. Certainly different types of cooperative learning impact on each of these variables differently. But in general cooperative learning approaches improve many things that in turn accelerate achievement, including class cohesion, teacher-student relations, self-concept, and social skills. Suffice it to say here that cooperative learning produces a host of positive effects on many variables that have a proven positive effect size on academic achievement, as illustrated in the table.

Cooperative Learning Boosts Achievement
Via Mediating Variables32

Mediating Variable

Effect Size

Percentile Gain

Teacher-Student Relationships



Small-Group Learning



Classroom Cohesion



Peer Influences



Peer Tutoring






Self Concept



Formative Evaluation






Social Skills



Reducing Anxiety






Classroom Management



Decreasing Disruptive Behavior



Future Research

The effect size research reported in studies of cooperative learning and Kagan Structures suggests important directions for future research.

What is the Impact of Different Structures? The Numbered Heads Together experiments by the SUNY research team produced very positive effect sizes favoring both forms of NHT over traditional WCQ&A. Those experiments, however, used an older version of NHT. Essentially students were asked a question, discussed their answers in their teams, were told to make sure everyone knew the answer, and then a student number was called and that student responded to the question. Two major advances in NHT have been made since the SUNY research was conducted. First, an "individual write" has been inserted before students discuss their answers in teams. This creates individual accountability so each student must respond first on her/his own, avoiding the possibility of a student giving no thought to the question and just waiting for teammates to tell the answer. Second, when a number is called, rather than having just one student respond, various simultaneous response modes, like response cards, are used to have all students whose number is called respond. This dramatically increases accountability and active engagement.

Structure Functions Interpersonal Functions 1.	Classbuilding 2.	Teambuilding 3.	Social Skills 4. Communicaiton Skills 5. Decision-Making Academic Functions 6. Knowledge Building 7. Procedure Learning 8.	Processing Information 9. Thinking Skills 10.	Presenting InformationThe limited question becomes whether effect size would be even greater for NHT by including these improvements. The broader direction for cooperative learning research is to determine the different effect sizes produced by different structures and different variations on structures. Essentially effect size gives us a tool to use as we develop a research-based pedagogy. The research by the SUNY team takes a first step in that direction, determining the additive benefits of an incentive package. With a dedicated research program, we can determine which structures and which variations on structures produce the greatest gains for different learning objectives. We can create a science of pedagogy!

Kagan Structures have been categorized by function: Ten functions have been identified.33 See Box: Structure Functions. For example Sage-N-Scribe is presumed to work best to create Procedure Learning whereas Quiz-Quiz-Trade is presumed to work best for Knowledge Building. Effect size provides a tool with which we can test the size of effect of different structures for different functions.

What is the Impact of Different Approaches to Cooperative Learning? There have evolved different schools of cooperative learning. Among the most prominent cooperative learning approaches are the Kagan Structures,34 Johns Hopkins Student Team Learning,35 Johnson and Johnsons' Learning Together,36 and Aronson's Jigsaw.37 In addition Kagan and Sharan independently developed Co-op Co-op38 and Group Investigation39 for project based learning. Further, there are a variety of more loosely defined approaches categorized as collaborative learning. These different methods have different functions. Effect size research can be used to determine the differences in impact of different approaches for different functions.

Does Cooperative Learning Impact on Different Groups Differently? There are some intriguing findings in the effect size research that merit future investigation. In the meta-analysis of cooperative learning for college and university students, effect size was substantially greater for African American and Latino students (.76) than for white students (.46) and heterogeneous groups (.42).40  We need to know if these ethnic or cultural differences are replicable across different populations. If so, the reasons for these differences merit exploration. Although cooperative learning produces substantial gains for all groups, it is possible that it is most powerful for lower achieving groups or for those less motivated by traditional instructional practices.


The present paper focuses narrowly on what effect size research tells us about cooperative learning and Kagan Structures. From the review we can conclude three things:

  1. Cooperative Learning has a very powerful positive impact improving student achievement.
  2. Kagan Structures have a positive impact even greater than most approaches to cooperative learning.
  3. Cooperative Learning and especially Kagan Structures improve an impressive number of variables with proven positive impact on student achievement.

The present paper does not overview the sizable body of empirical research showing the positive impact of Kagan Cooperative Learning. For an overview of that research which covers the range of grades and content areas, I refer you to the research section of the Kagan web page41 and to the mini-book, Kagan Cooperative Learning Structures.42

The overall impact of effect size research is to focus educators not just on what makes a reliable difference, but rather on what makes an important difference. Effect size research makes it clear that cooperative learning and Kagan Structures stand out as among the most powerful tools for educators who strive to substantially accelerate achievement and improve a host of additional positive outcomes.