Project-Based Learning

The Hattie Effect: What's Essential for Effective PBL?

In the daily bustle of the classroom, teachers can't hit pause to evaluate the effectiveness of every decision they make. And those judgment calls pile up. From how to plan lessons to whether students should collaborate to how much homework to assign, daily decisions about instruction number in the hundreds.

John Hattie, an education professor and researcher in Australia, has done the wonky work of evaluating mountains of data to determine which decisions make the biggest difference when it comes to learning. His two books, Visible Learning and Visible Learning for Teachers, have triggered global conversations about effective teaching, based on his meta-analysis of more than 800 studies.

Hattie's work promises to demystify what works in education. Indeed, a BBC interviewer recently compared his research to the holy grail of education and asked him for a thumbs-up or thumbs-down about common classroom practices. To paraphrase Hattie's responses: Homework? Hardly worth the time. Small class size? Minimal effect. Teacher talk? OK for introducing new information but a poor route to deeper learning. Ability tracking? Don't do it. School uniforms? Meh.

Aiming for Effectiveness

Hattie's findings are based on a comparison of effect size. That comparison is critical, he argues, because virtually everything teachers do affects student learning. But all effects are not equal. Good teachers make a habit of applying those strategies that produce the greatest effect size. Teaching quality could improve dramatically, it follows, if teachers would favor interventions that produce at least average gains.

He has identified a "hinge point" of 0.40 to identify actions "that could be considered 'working' in terms of making a visible difference in student learning," as he explains in Visible Learning for Teachers. The hinge point "is close to the average effect that we can expect from a year's schooling." Or, as he puts it, a year's growth for a year's effort.

So far so good.

A Need to Know More About PBL

But when it comes to evaluating the effectiveness of project-based learning (PBL), Hattie has me scratching my head. Part of the challenge is that he doesn't focus specifically on PBL, and certainly not on PBL that is designed with an emphasis on high-quality teaching and learning. Problem-based learning winds up near the bottom of teaching effects (0.15). Inquiry-based teaching ranks a little higher (0.31), but still below the hinge point. Meanwhile, Piagetian programs, emphasizing challenges that cause learners to apply higher-order thinking and learn collaboratively (sounding similar, at least in spirit, to PBL) rank near the top (1.28).

What's more, many of the essential components of PBL turn out to be highly effective. Formative assessment, critical for project success, comes in at 0.90. Feedback, another key to PBL, has an effect size of 0.73. Challenge and practice at the right level: 0.60. Valuing error and creating trust: 0.72. It's hard to imagine a PBL classroom where those factors are not present.

When Hattie himself synthesizes what matters most for learning, he describes an effective classroom in language that is completely consistent with a PBL environment:

Visible teaching and learning occurs when there is deliberate practice aimed at attaining mastery of the goal, when there is feedback given and sought, and when there are active, passionate, and engaging people (teacher, students, peers) participating in the act of learning.

Expanding the Conversation

So, what can PBL advocates make of Hattie's findings?

For starters, it's worth remembering that PBL is not just one thing. Designing, managing, and assessing projects involves a wide range of teacher behaviors and decisions. During projects, teachers can deliberately emphasize those strategies that research shows to be highly effective -- such as formative assessment, feedback, learning from errors, setting goals, and self-monitoring. They can avoid inquiry that is too unstructured, which may not deliver strong results, and design projects with specific learning goals in mind.

Next, we need more clarity about what makes for effective PBL. Just as all teaching doesn't get equal results, so it goes with projects. As John Dewey reminded us a century ago, "The belief that all genuine education comes about through experience does not mean that all experiences are genuinely or equally educative."

(To understand what researchers have to say specifically about PBL, take a look at this comprehensive research summary.)

My colleagues at the Buck Institute for Education (@biepbl) are currently developing a "gold standard" for project-based learning that will define what's essential for high-quality PBL. BIE Executive Director John Mergendoller kicked off this conversation during the PBL World conference in June. Among his suggestions: the gold standard needs to focus more directly on "the teacher in the classroom." (Here's a recording of my follow-up conversation with him.)

Teachers, school leaders, researchers, and others who are interested in PBL are invited to weigh in on what the gold standard should include. Join the conversation by using the Twitter hashtag #goldstandardPBL or take part in a series of online events that BIE is hosting. Mergendoller, eager for this conversation to be inclusive, invites comments from around the globe. Add your thoughts to his recent blog post on gold standard PBL.

Share your thoughts in the comments here, too. How do you apply research about teacher effectiveness in your classroom decisions? How has Hattie's research shaped your thinking about what works in PBL?