Two key articles give us some of the first evidence in medical education that applying multimedia design principles affect learning.
The first article is a prospective study where “traditional” powerpoint slides were compared to “modified” powerpoint slides in a 50-minute lecture on shock given to third year medical students during their surgery clerkship. The modifications were based on Mayer’s multimedia design principles. A pre-test/post-test control group was used and took a convenience sample of students (39 in the control group, 91 in the modified slide group).
The author, Dr. Nabil Issa, was gracious enough to send me the slides he used in his study. I have included the ones that appear in the two articles for comparison.
“Before”
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“After”
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Results: Both groups showed improvements in retention , transfer, and total scores between pre- and post-tests. However, further analysis showed statistically greater improvements in retention (F=10.2, p=0.0016) and total scores (F=7.13, p=0.0081) for those students in the modified slide group. Interestingly, there was not a significant difference between the groups ability to apply the new knowledge to clinical vignettes.
The second article is a follow-up study based on the first.
Results: The modified slide group significantly outscored the traditional slide group on delayed tests of transfer and retention given at 1 week (d=0.83, 0.83 respectively) and 4 weeks (d=1.17, 0.83 respectively) after initial instruction. The modified slide group also significantly outperformed the traditional slide group on immediate tests of retention and transfer. (see below)
So, what does this mean for us. Well, a few things. First, we have evidence that the way we design our materials affects learning. It also means we have a lot of work to do. There are many more questions to answer to fully understand the effect of incorporating multimedia design principles. Are certain concepts taught better in certain ways? Does the length of the presentation affect retention (yes on this one, but just thought I would throw it out there)? How do we best teach others to design with multimedia principles?
Hopefully, this is the first of many studies on optimizing the delivery of content to our learners. I even hope to contribute to this body of literature myself in the coming years.
I have written previously on Mayer’s work in this blog if you are looking for more information about multimedia design principles. Click here to see the page.
Below is a diagram of the cognitive theory of multimedia learning: 
(Click to enlarge)
References:
Presentation Design for Medical Educators 