Sunday / July 21

Unpacking Effective Project-Based Learning

project-based learning

Visible Learning

Educators all over the world are buzzing about John Hattie’s research on visible learning. In his research, Hattie asserts that “almost everything works” to some extent. In other words, every intervention will impact students in some way. However, only certain interventions have a significant or “visible” impact on student achievement. Hattie performed a meta-analysis of over 800 studies to determine the effect size (statistical measure of change) of many different interventions. He then identified an effect size of 0.4 as the “hinge-point” or the level at which an intervention makes a significant or visible impact on students.

Some of Hattie’s results were predictable while others challenged commonly held assumptions among educators.  Here are a few examples:

Influence Effect Size Interpretation
Student Expectation 1.44 Highly effective
Teacher credibility in eyes of students 0.9 Highly effective
Feedback 0.75 Highly effective
Reciprocal teaching 0.74 Highly effective
Teacher-student relationships 0.72 Highly effective
Metacognitive strategies 0.69 Highly effective
Acceleration 0.6 Highly effective
Concept Mapping 0.6 Highly effective
Cooperative learning 0.59 Moderately effective
Direct instruction 0.59 Moderately effective
Teacher expectations 0.43 Moderately effective
Individualized instruction 0.22 Not visibly effective
Reducing class size 0.21 Not visibly effective
Student learning styles 0.17 Not visibly effective
Ability grouping 0.12 Not visibly effective
Teacher subject knowledge 0.09 Not visibly effective
Student control over learning 0.04 Not visibly effective
Retention -0.13 Negatively effective

Information adapted from

Is PBL Invisible?

This research gives educators important insights into which teaching methods and models have the greatest impact on student achievement outcomes. However, it reported that a contemporary and prominent teaching model, project-based learning, has an effect size of only 0.15. According to Hattie’s research, then, this teaching method does not have a significant impact on student learning. Although Hattie’s analysis of PBL included 285 studies, providing a significant and reliable sample size, there are several other factors that must be considered before writing off the teaching model all together.

PBL Is a Vehicle

Before discussing the visibility of PBL, it is important we agree upon an understanding of what it is. Firstly, PBL is not the same thing as “doing projects.” Although a PBL unit usually results in a project outcome, the process of applying various academic concepts to solve a real-world problem is what distinguishes a PBL. John Larmer and Dr. John R. Mergendoller of the Buck Institute for Education, identified 8 essential elements to project-based learning:

  • Significant content
  • A need to know
  • A driving question
  • Student voice and choice
  • 21st century competencies
  • In-depth inquiry
  • Critique and revision
  • Public audience

Although, according to Hattie’s research, PBL has a much less significant benefit than more traditional teaching models such as direct instruction, it is important to consider that PBL is a model that, when done well, allows a teacher to combine highly “visible” influences such as:

  • Feedback
  • Reciprocal teaching
  • Micro teaching
  • Acceleration
  • Metacognitive strategies
  • Vocabulary
  • Creativity
  • Self-verbalization and self-questioning
  • Problem solving teaching
  • Cooperative learning
  • Tactile stimulation
  • Questioning

Even direct instruction is a small but important piece of the PBL process. However, it would be difficult to isolate the effect of problem-based learning when these other influences are factored out. In fact, most models of instruction would be ineffective if siphoned of these other influences. Instead, PBL should approached as a vehicle to combine many of these other influences than are intrinsically more visible. It combines visible learning factors but is not a magic-bullet that will yield high student achievement if it does not include all this other “good stuff.”

PBL is Hard Work

As Bryan Goodwin points out in his book Simply Better, the effectiveness of an instructional model depends greatly on how it is delivered. He asserts “researchers often have trouble discerning whether programs are ineffective due to faulty design or poor implementation.”

Perhaps this phenomenon plays a role in why PBL is not proving to be a highly visible instructional model.  Many teachers struggle to effectively implement the PBL process, not for lack of effort but because it is difficult and requires practice. A PBL unit may look good on paper, but its success depends greatly on the teachers ability to:

  • Scaffold background knowledge
  • Facilitate meaningful student discussion
  • Allow for risk-tasking
  • Build a culture around growth mindset
  • Ask higher-order questions
  • Give effective feedback
  • Direct inquiry and inferencing

All of these are difficult to combine effectively. And for many teachers, they are very different from the teaching we grew up with or even learned about in our teacher education programs. However, as we practice facilitating PBLs with our students, all of these things become more natural, resulting in significant student growth.

PBL’s “Invisible” Benefits

If direct instruction yields more visible student outcomes and is easier on the teacher, why go to all of the trouble of doing a PBL?  Many teachers are asking themselves this same question. But the answer is found in considering one fact.  Hattie’s research only measures student achievement on a test. To be fair, those tests scores are important as they play an increasing role in student placement, acceptance into higher education, teacher and school evaluation, and even teacher pay. It does not, however, assess a student’s readiness to live in an ever-changing, digital, global, and innovation-based society.

A well-done PBL offers the additional benefits of preparing students with other essential 21st Century skills such as:

  • Creativity (applying knowledge to solve authentic problems)
  • Collaboration (effectively and respectfully interacting with others)
  • Communication (listening, speaking, and combining ideas)
  • Critical thinking (approaching a problem from a fresh perspective)
  • Technology application (discovering and applying new technologies in a useful way)
  • Analytical, applied writing (writing for a purpose)
  • Growth mindset (risk-taking)
  • Authentic audience (communicating results in a way that gives purpose to learning)

Striking a Balance

A balanced approach to pedagogy is essential. We must use our precious time in a way that yields measurable academic benefits for our students but we cannot neglect the moral imperative to prepare our students for their future–a future that is very different from our past experiences. So before we write off project-based learning, let’s give it another chance and embrace the opportunity to improve our pedagogy. John Hattie himself said, “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 participating in the act of learning.” Let’s be and lead those people.


Goodwin, B. (2011). Simply better: Doing what matters most to change the odds for student success.  Alexandria, VA: ASCD.

Hattie, J. Visible learning for teachers.  Retrieved February 28, 2015 from

Hattie, J. Visible learning, tomorrow’s schools, the mindsets that make a difference in education.  Retrieved February 28, 2015 from

Larmer, J. and Mergendoller, J.R.  Eight essentials for project-based learning.  Retrieved February 28, 2015 from

Written by

Miranda Reagan worked two years as a STEM teacher and technology coordinator at Sam Houston Elementary School in Maryville, TN. In this capacity, she has designed and implemented lessons for a K–3 STEM lab and mentored teachers in “STEM-infusing” their classrooms. Last year, Miranda was a full-time instructional coach where she served as a resource to teachers for STEM-infusion and technology integration. Because of her passion for children, she moved back into the classroom to teach 3rd grade, using the STEM-infusion method of instruction in a 1:1 iPad classroom. Miranda Reagan’s book entitled STEM-Infusing the Elementary Classroom will be available from Corwin in March 2016.

No comments

leave a comment