With headlines
like “Drinking water improves exam grades”1 and “How to do better in your exams:
Drinking a glass of water can boost your results by a grade”2 in all the top
newspapers and news websites, it would hard to dismiss their claims. However
all of the articles simply regurgitate and reiterate the exact same press release
from the British Psychological Society, in which this research was presented at
their annual conference this month3.
The research was interesting because it seemed to claim
that by simply encouraging students to take water in to the exam with them they
would be able to improve their exam grades. The BBC ’s article
on this research included the following statement: “Also, supplementing with
water is a really cheap way students and educators can help get better
results.” They went on to claim the results could be due to the benefits of
hydration and stress relieving qualities of water.
This
research extrapolates from an observation in a small number of subjects, and it
is a typical leap of ‘correlation must mean causation.’ The study did not
suggest the far more likely reason that students who take water in to their
exams do better than students who don’t, which simply boils down to
preparation. Students who take a mature approach to their studies are likely to
study in a more structured and efficient manner, and are likely to be very
prepared for the exam. Part of being prepared for an exam would be thinking of
every eventuality and organising yourself to take everything you might need in
to the exam with you, and that would include taking water.
This
explains the observation that the percentage of students taking water increases
in second and third year of university, because students are learning how to
prepare for exams and are becoming more organised. If the researchers honestly
thought that the water was the cause of the improved grades then they would
carry out a randomised trial, where they took a group of students and randomly
assigned half of the students a bottle of water to take in to the exam and then
determine if there was a significant difference. What is more frustrating is
that this research has taken the media by storm, but has not been critically analysed
and peer reviewed before hand, as it has not yet been submitted for
publication. Peer reviewing of such research would highlight the need for
increased numbers of study subjects and the implementation of randomised trials,
before releasing claims that water can improve exam grades, as this is likely
to be a fallacy.
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