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Lessons from John Hattie: Unlocking the Power of Classroom Discussion

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April 11th, 2019

This article was co-written with David Stevens, Berkeley Unified School District

Imagine you went to see your doctor about a cold and she recommended a particular treatment. You, in turn, ask the doctor why she thinks it is the right option. In one scenario she replies: “I’ve heard it works, and it is also what my mother always did.” But in a second scenario the doctor’s response is: “The New England Journal of Medicine published a study recently of 10,000 patients in a randomized, controlled trial showing that this treatment resulted in statistically-significant better outcomes, and that the magnitude of the impact was substantial.” Most likely the latter response would inspire you with more confidence in your doctor’s advice. Evidence matters in medicine, and so it should in educational practice as well.

John Hattie, whose work is becoming increasingly influential in the field of education, similarly endorses the importance of selecting educational practices, both instructional and structural, based not just on evidence, but on impact. His endeavor to analyze the effectiveness of educational practices and rate their impact on student achievement resulted in his widely-acclaimed book Visible Learning.

In that text, he acknowledges that most everything we do in education “works,” in that it has an effect that is positive on student achievement. However, just like flying first class versus flying coach, while both can get you to your destination, nobody would claim that they give you the same experience. Similarly, Hattie’s work demonstrated that some educational practices have greater impact than others—and are therefore more deserving of our attention and investment. Examples include direct instruction, response to intervention or RTI, and feedback to students. Another is our focus for today: class discussion.

Discussions as a Source of Data

Class discussions are so routine a practice in schools that they hardly seem to warrant advocacy. They are used primarily as a tactic to raise student engagement, often as an “ice-breaker” activity or to activate students’ prior knowledge around new content. But class discussions can also be sources of rich, qualitative data—data that allow teachers to understand the thinking of their students more closely and determine if there are information processing errors that need instructional intervention, the more immediate the better.

When students are instructed to discuss what they are learning, teachers can listen to gauge the depth of what they know and, if that understanding proves too shallow, expand or challenge their thinking before moving forward. This is especially valuable if that material is being built on in future lessons. Or, if students express misconceptions around what they are learning, a teacher can confront those errors in that context, providing clarity before it is further cemented in their students’ memories. This all means teachers are able to react to students’ thinking with a nuance and precision unlike many computer-adaptive or pre-packaged personalized learning programs, which maximize learning time for all.

Class Discussions and Cognitive Load

Part of the challenge with class discussion is that there is no definitive “recipe” for increasing its effect on student achievement. In fact, the flexibility and autonomy it offers teachers is part of what makes class discussion such a powerful instructional practice. There is one important guideline to keep in mind, however, and that is related to cognitive load: during effective class discussion, ensure that the students are doing the deep thinking and talking about the material—not the teacher. While this seems rather obvious, it is also an incredibly simple slight for any well-intentioned educator to make in the midst of an exciting—or very quiet—exchange of ideas. We encourage you to see for yourself: observe a class discussion at your school and track the minutes of teacher versus student talk (not to mention the quality of what is said in those minutes). When teachers value class discussions as sources of data to guide them in making the right, most precise instructional decisions, cognitive load inevitably falls on the student as does the benefit.

Discussions in Tandem with Technology

Class discussion complements the effectiveness of other instructional tools, especially educational technology. In many cases, when technology is introduced initially to teachers, it is done in isolation rather than integrated with other instructional practices; this is in large part because learning a new tool with a new interface can be challenging enough. Class discussions are daunting for teachers in their own ways, as they must manage the participation of students as well as the content they express, all toward a common class objective. Yet when paired together, they can enrich the experience for student and teacher alike.

For instance, before having students respond to questions using an online platform, teachers can instruct them to discuss briefly with a partner. Teachers gain insight into how students are interpreting questions (giving the teacher an opportunity to clarify or redirect). As a result of discussion prior to writing, students generate more thoughtful responses with deeper analysis and more complex ideas.

Additionally, many online learning tools allow teachers to view and select individual students’ responses to either use as models or deepen further discussion for the whole class. In this way, teachers leverage the thinking of students to drive instruction and understanding. Teachers can also use the whole-class views to make more strategic decisions about which students to call on or how to nudge students’ thinking in advance—important for any educator wary of wasting valuable class time.

Hattie’s Word to the “Why”

As with all instructional strategies Hattie has studied, more of something—even something with a large effect size like class discussion or feedback to students—is not always better. In the case of feedback, for instance, Hattie warns us that simply delivering more of it to students will not result in “magical increases in achievement” without an understanding as to its role in learning. He notes that many misinterpret its benefit in this way: “it is the feedback to the teacher about what students can and cannot do that is more powerful than feedback to the student.” Feedback to the teacher in itself is agnostic to learning—it is the teacher’s response to the feedback that drives powerful learning. While technology can provide insights, we should not underestimate the import of the skilled and nimble educator. Technology serves the role as catalyst, accelerating the impact of instruction.

Ultimately, Hattie wasn’t just sharing that classroom discussions are a high-impact instructional practice. A key takeaway is that discussion (and any instructional practice) needs to be perceived and implemented through the right lens in order to unlock that higher impact—which, in the case of classroom discussion, is not necessarily happening in classrooms. This is an important shift in how we view the purpose and value of many of the high-impact instructional practices like classroom discussions—and, reveals an important shift needed on the part of educators.

True chefs are fond of saying “following a recipe” and “cooking” are not the same thing. The former can make you a nice meal. The latter involves the dynamic process of tasting and adjusting until the flavor balance is just right—with results that can be magical. Similarly, while implementing a good lesson plan can move students in the right direction, great lessons will include an iterative process between feedback from the student and instructional adjustments by the teacher.

Perhaps this is the most important takeaway from Visible Learning. If class discussions are assigned simply for enhancing student engagement, there will be a positive benefit. But it will not be as positive or as powerful a benefit as when teachers use class discussion data to adapt instruction. Building the capacity to view class discussions as sources of student data can make for stronger, more effective teachers with larger effects on student achievement long-term. The more we support teachers to view class discussions as data, the more students will reap the benefits of those important, in-the-moment changes educators make based on class discussion data.


Illuminate Education is a provider of educational technology and services offering innovative data, assessment and student information solutions. Serving K-12 schools, our cloud-based software and services currently assist more than 1,600 school districts in promoting student achievement and success.

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  1. Zenaida Figueroa on May 6, 2019 at 10:24 am


  2. Lynne Fox on February 11, 2020 at 6:54 pm

    Two thoughts in this article really struck me. First I appreciate the underscoring that technology is not the end-all, be-all, but when integrated with a good teacher who skillfully implements it as an added tool, it can help lead and streamline discussions. The comparison between arriving at a destination via coach or first class is graphic and makes me rethink what service my students are receiving.
    Second, “Following a recipe” vs. “Cooking.” This says it all to me! The magic happens when the chef (teacher) is involved with his head and his heart and understands what he hopes to put on the table.

  3. […] Read Illuminate Education’s blog entry. Read this individually or with your elbow partner. […]

  4. […] My school campus has spent many professional development hours focused on strategies and processes that develop and encourage strong classroom discussion.  We have invested time in this because we know its effect size on student achievement. […]

  5. sharon k vanis on July 16, 2020 at 10:47 am

    Student led discussions are really insightful. You have to have the right mix and comfort in your classroom or it can be very quiet and uncomfortable. Start discussions with topics the kids are comfortable with and then as you move into other topics even though they may not be comfortable because they have been doing the student led discussions I think it will be more effective and productive.

  6. Classroom Discussion - Dr. Katherine Stover on August 16, 2020 at 8:08 am

    […] Lessons from John Hattie: Unlocking the Power of Classroom Discussion […]

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