gms | German Medical Science

GMS Journal for Medical Education

Gesellschaft für Medizinische Ausbildung (GMA)

ISSN 2366-5017

A Summary and Commentary on Smith et al.'s "Why peer discussion improves student performance on in-class concept questions" (Science 2009)

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  • corresponding author Christian Scheffer - Universitšt Witten/Herdecke, Integriertes Begleitstudium Anthroposophische Medizin, Witten, Deutschland

GMS Z Med Ausbild 2011;28(1):Doc08

doi: 10.3205/zma000720, urn:nbn:de:0183-zma0007201

This is the English version of the article.
The German version can be found at:

Received: September 7, 2009
Revised: September 27, 2010
Accepted: October 5, 2010
Published: February 4, 2011

© 2011 Scheffer.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Food for Thought – Recommended Reading on Education Issues

A Summary and Commentary on Smith et al.’s “Why peer discussion improves student performance on in-class concept questions” (Science 2009)


What effect do group discussions have on successful learning? Must an expert who knows the correct answer be present during a discussion to ensure the group comes to the right conclusion?


When students answer an in-class conceptual question individually using clickers, discuss it with their neighbors, and then revote on the same question, the percentage of correct answers typically increases. This outcome could result from gains in understanding during discussion, or simply from peer influence of knowledgeable students on their neighbors. To distinguish between these alternatives in an undergraduate genetics course, we followed the above exercise with a second, similar (isomorphic) question on the same concept that students answered individually. Our results indicate that peer discussion enhances understanding, even when none of the students in a discussion group originally knows the correct answer [1].

Summary of the study:

It is a well-known phenomenon that students are better able to answer a question after having discussed it in small groups. Smith et al.’s study investigated whether students actually gained in understanding during small group discussion or whether they were, in fact, influenced by other knowledgeable students within the group. In an introductory genetics course at the University of Colorado-Boulder in the USA, a total of 350 students were asked five questions per class period throughout the semester, which they answered electronically using “clickers”. Once the students had answered the question individually, they were then asked to discuss the question with their neighbors and once again enter their answer. Later on, the students were asked a similar question on the same concept but with a different context (“isomorphic question”).

Two of the study’s results led the authors to conclude that students had learned from discussion with their peers. First, the percentage of correct answers to the first question after discussion and to the second isomorphic question was higher. Second, of the students who answered the first question incorrectly before group discussion but correctly after discussion, 77% answered the isomorphic question correctly. This indicates that the students were able to apply what they had learned during discussion to a different context. By contrast, not only did students who answered the first question correctly on their own not change their opinion during group discussion, they also tended to answer the second question correctly. Even 44% students who answered the first question incorrectly both before and after group discussion were able to answer the second question correctly (when given four possible answers to choose from). Therefore, a learning process obviously took place after the discussion. Surprisingly, there were also small groups, in which no one initially knew the correct answer to the question but who came to the right conclusions together after the discussion. This suggests that the individual students learned from the discussion process.

The authors concluded that peer discussions contribute significantly to successful learning and that this learning can be attributed to gains in conceptual understanding rather than mere peer influence. Since students arrive at the correct answers both during and after group discussions in which an “expert” who knows the correct answer is not initially present, it seems that the discussion process promotes conceptual understanding and is not merely a matter of the expert student transmitting the correct answer to his peers.


This study was published in “Science,” a leading scientific journal, which indicates that the publishers found significance in the conclusions drawn from this rather basic experiment. The study’s findings that peer discussion can be used as a didactic teaching method toward promoting successful individual learning and gaining understanding through the collective knowledge of group members present a number of implications for didactic instruction. Not only do they support the use of short interactive discussions during lectures and seminars; they also enhance the theoretical foundations of problem-based learning. The question also arises as to whether more targeted use of group discussions could be made in clinical education and practice as well. One limitation of the study that should be noted, however, is that it focused solely on conceptual questions. In other words, it dealt with questions that are answered through learned understanding and not pure knowledge (factual) questions.

Competing interests

The author declare that he has no competing interests.


Smith MK, Wood WB, Adams WK, Wieman C, Knight JK, Guild N, Su TT. Why peer discussion improves student performance on in-class concept questions. Science. 2009;323(5910):122-124. DOI: 10.1126/science.1165919 External link