#KeyLIMEPodcast 256: Surviving a lecture? A great lecturer can be bad for you(r learning)

Jon’s selection examines an age old problem: What is the most effective way to deliver a large group session? The  study examines two contrasting methods: active learning and passive lecture. The students were then asked to complete a self-reported survey on their perception of learning, as well as an MCQ test. What’s your guess on the results? (hint: Jon suggests this episode should be shared with that colleague who may be notorious for Death by PowerPoint). Listen here.


KeyLIME Session 256

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Deslauriers et. al., Measuring actual learning versus feeling of learning in response to being actively engaged in the classroom. Proc Natl Acad Sci U S A. 2019 Sep 24;116(39):19251-19257.


Jon Sherbino (@sherbino)


A little known fact about me is that I am a failed theoretical physicist. If not for the math, I imagined a career pondering the universe and writing equations on a blackboard a la “Good Will Hunting.” So when I cam upon this paper it was too good to pass – an instructional methods paper from the Harvard physics department. (As an aside, the physicists at Harvard are serious educators. A shout out to Eric Mazur who developed the concept of peer instruction that relied on educational seat assignments, positioning low performers at the front and high performers in an encircling ring around the class.)

The paper tackles a century old problem.. how to deliver an effective large group session. There are a number of issues at play.

  • Most lecturers adopt a death by PowerPoint ethos.
  • Active learning strategies, while effective to improve attendance, engagement and acquisition of knowledge, are resource intensive.
  • Moreover, despite student’s hatred of DPP (death by power point) they equally disdain active teaching, citing little desire to interact with other students, among other issues.


Our study sought to measure students’ perception of learning when active learning alone is toggled on and off… We compared actual learning to students’ feeling of learning … following each of 2 contrasting instructional methods: active learning (experimental treatment) and passive lecture (control).”

Key Points on the Methods

This was a two-arm, randomized, cross-over study. Students were randomized to active learning or passive learning. Active learning involved an instructor delivering a lecture complemented with small group work requiring students to solve example problems with tailored feedback provided by the instructor and regular student interaction and discussion. Passive learning involved an instructor only delivering a lecture; example problems were solved by the instructor without student input.

Two physics topics were covered in a 90 minute session. The two topics were spaced apart by two days within the same week. Each group crossed over from active to passive manipulation between topics. The protocol was repeated once with a new cohort of students.

Slides and handouts were identical between study arms. Students had no prior exposure to the instructors.

At the end of each teaching session, a self-report survey on the student’s perception of learning and a 12 item MCQ test were completed. The MCQ test was constructed based on the learning objectives for the session, not on the material delivered. The instructors did not have access to the MCQ tests.

Ethics review was exempt as “this study involved classroom-based research using normal educational practices…”

Key Outcomes

149 (of 157) students participated.

Using a 5-point Likert scale, students in the passive instruction arm:

  • enjoyed the lecture more,
  • reported increased learning,
  • reported improved instructor effectiveness, and
  • desired all physics courses to adopt this model.

All of these comparisons were statistically significant. The difference in mean scores were approximately 0.5 points. There was no difference between topics.

MCQ scores were higher and statistically significant for the active instruction arm for both topics. The difference between arms was approximately 10%.

A fixed effects linear regression model showed that active learning instruction led to almost half a standard deviation improvement in tests of learning (p<0.001).

Key Conclusions

The authors conclude…

“… we find that students’ perception of their own learning can be anticorrelated with their actual learning under well-controlled implementations of active learning versus passive lectures… students can be misled by the inherent disfluency associated with the sustained cognitive effort required for active learning, which in turn can have a negative impact on their actual learning.

… the cognitive fluency of lectures can mislead students into thinking that they are learning more than they actually are … novices in a subject have poor metacognition and thus are ill-equipped to judge how much they have learned … students who are unfamiliar with intense active learning in the college classroom may not appreciate that the increased cognitive struggle accompanying active learning is actually a sign that the learning is effective.”

Spare Keys – other take home points for clinician educators

A quick spare key… another physicist with a #meded pedigree is Geoff Norman.


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