The spacing effect and semesterisation

Greg Foley, Lecturer in Bioprocess Engineering, School of Biotechnology


There is a well-established phenomenon in learning science and it is known as the spacing effect. This effect is illustrated schematically in the figure below. Basically, it is something we all intuitively know, namely the more times we revise material the more it sticks in our memory. Our instinctive awareness for the spacing effect is the reason why we advise our students not to cram for exams but to study continuously through the year.


Ideally, a student should study regularly and often (but not too often because it turns out that it’s good to forget and re-learn), but in each study session he/she should not only cover the most recent material; on the contrary, parts or all of the accumulated material up to that point should be revisited. In reality, this means that study sessions should get longer and longer as exam time approaches. It goes without saying that it is challenging to study like this because it demands a lot of commitment and sacrifice especially in the smartphone age.

The question is, therefore: does our current, very condensed semesterised system make it more difficult for students to study effectively? It is interesting that in the US where the semester system has long been the natural order of things, good learning and study practice is more or less enforced through the use of homeworks, quizzes, mid-terms and finals. Testing is frequent and because there is so much of it, the stakes in any given test are not so high as to be overly stress-inducing. Crucially, this means that you can set assignments/ problems that really test the student’s ability to think critically and creatively without severely penalising weaker students.

For sure we have continuous assessment components in many modules and this does help to reduce failure rates, but paradoxically this might be part of the problem. Suppose you have a CA component that accounts for 20% of the final module mark and it involves a couple of undemanding in-class tests covering small chunks of material, material that in many cases is re-examined in the final exam. Now suppose a student gets 70% on that test, a common occurrence in my experience. (CA marks tend to be much higher than exam marks.) Then the student only has to get 33% in the end-of-semester exam to pass the module. That’s quite a low bar and an average student will be able to get over it with little more than a short period of cramming.

Even without a CA component,  the chunks of material that students have to revise in a semesterised system are relatively small anyway. Now combine this with the fact that most lecturers provide  online notes, thus encouraging low attendance rates, and you get a ‘perfect storm’ in which students are almost incentivised to learn ineffectively.

The really worrying thing about all of this is that if students put their faith in cramming, much of what they will have learned will be rapidly forgotten, maybe even before the start of the next semester. The knock-on effects are both serious and obvious.

Of course, the horse has bolted and there is no going back to non-semesterised ways but we may perhaps need to do some hard thinking about the very nature of third level education here in Ireland. We seem to have put a lot of our eggs in the ‘independent learning’ basket but it is hard not to think that we have adopted a system that encourages study habits that are inconsistent with effective independent learning.

Having studied in the US, I think the US approach might suit the Irish student of 2016. However, that would be problematic for a number of reasons, not least the fact that the American system is underwritten by cheap labour in the form of teaching assistants.



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