Why effective presentation slides matter

Presentation software like Microsoft PowerPoint, Apple Keynote, and Prezi are ubiquitous in medical education and the business of healthcare. When used appropriately in a direct presentation format, these tools let educators display visual aids, emphasize key points, and interact with learners to promote their understanding.

Unfortunately, these widely used tools can also interfere with learning when used in suboptimal ways. Complex material has high intrinsic cognitive load, and poor presentation of complex material needlessly adds extraneous cognitive load.1-3

When designing slides for your presentation, consider the following best practices to reduce cognitive load and increase understanding:

Assertion-Evidence slide design

“Traditional” slide design includes a top-center headline phrase, followed by a bulleted list of information and/or a supporting image or figure. When used indiscriminately, bulleted lists can skew the presentation of information, whether by fragmenting, oversimplifying, or oversaturating.1-3

As an alternative, Assertion-Evidence (A-E) slide design encourages the following structure for each slide:

  1. A headline that contains the main assertion or message in the form of a sentence: This ensures that the most important information is clearly stated on each slide.
  2. Supporting evidence for the main assertion: Visual evidence is preferable over words. Bulleted lists are avoided.4 This means that speakers won’t be able to use slides themselves as presentation notes but must still be able to explain the evidence clearly.3

Studies comparing traditional slide design to A-E slide design in engineering and veterinary students have shown increased comprehension and retention of presented material in the A-E slide design group.3,5,6

Pearls for formatting presentation slides

  • Aim for legibility:
    • Use large font sizes. Sizes greater than 18 pt on text, graphs, and diagrams will ensure that learners in the back of the room will be able to read your slides.7
    • Choose simple fonts. Ornate or stylized fonts are less legible and make reading times slower.8,9
    • Apply high-contrast colors. This usually means light text on a dark background, or vice versa. Note that some color combinations can make reading challenging – e.g. red on blue, or green on red. Use bright colors with care, as they may be harsh on eyes when used in large amounts.10 Learners may have color blindness, so test your slides’ color combinations using a color blindness simulator.
    • Avoid centering text. Remember that English readers read from left-to-right, and blocks of text are usually left-justified.
  • Find the right diagram for the task. As an alternative to bulleted lists, ask if information can be displayed differently. For example, a list of times or dates may be better understood as a timeline.3
  • Avoid using unrelated “clip art”, graphics, or sound effects. Research has shown that unrelated content can decrease recall and generally aren’t favorably viewed by learners.1
  • Strive to keep slides “light”. Studies suggest displaying no more than 20 projected words per minute. Try to keep blocks of text to 2 lines at the most.3
  1. Bartsch RA, Cobern KM. Effectiveness of PowerPoint presentations in lectures. Computers & Education. 2003;41(1):77-86. doi:10.1016/S0360-1315(03)00027-7.
  2. Craig RJ, Amernic JH. PowerPoint Presentation Technology and the Dynamics of Teaching. Innovative Higher Education. 2006;31(3):147-160. doi:10.1007/s10755-006-9017-5.
  3. Root Kustritz MV. Effect of Differing PowerPoint Slide Design on Multiple-Choice Test Scores for Assessment of Knowledge and Retention in a Theriogenology Course. Journal of Veterinary Medical Education. 2014;41(3):311-317. doi:10.3138/jvme.0114-004R.
  4. Alley M. The Craft of Scientific Presentations. New York, NY: Springer New York; 2013. http://link.springer.com/10.1007/978-1-4419-8279-7. Accessed Oct 11, 2016.
  5. Garner JK, Alley MP. How the Design of Presentation Slides Affects Audience Comprehension: A Case for the Assertion–Evidence Approach. International Journal of Engineering Education. 2013;29(6). http://www.craftofscientificpresentations.com/uploads/5/6/1/4/56145985/ae_comprehension.pdf. Accessed Oct 13, 2016.
  6. Garner JK, Alley MP. Slide Structure Can Influence the Presenter’s Understanding of the Presentation’s Content. International Journal of Engineering Education. 2016;32(1A).
  7. Make your PowerPoint presentations accessible. Microsoft. https://support.office.com/en-us/article/Make-your-PowerPoint-presentations-accessible-6f7772b2-2f33-4bd2-8ca7-dae3b2b3ef25. Accessed Oct 13, 2016.
  8. Morrison S, Noyes J. A Comparison of Two Computer Fonts: Serif versus Ornate Sans Serif. Usability News. Aug 2003. http://usabilitynews.org/a-comparison-of-two-computer-fonts-serif-versus-ornate-sans-serif/. Accessed Oct 13, 2016.
  9. Bernard M, Lida B, Riley S, Hackler T, Janzen K. A Comparison of Popular Online Fonts: Which Size and Type is Best? Usability News. Jan 2002. http://usabilitynews.org/a-comparison-of-popular-online-fonts-which-size-and-type-is-best/. Accessed Oct 13, 2016.
  10. Lane R. Combining Colors in PowerPoint – Mistakes to Avoid. Microsoft. https://support.office.com/en-us/article/Combining-Colors-in-PowerPoint-–-Mistakes-to-Avoid-555e1689-85a7-4b2e-aa89-db5270528852. Accessed Oct 13, 2016.
  11. Tutorial for the Assertion-Evidence Approach. Assertion-Evidence Approach. http://www.assertion-evidence.com/tutorial.html. Accessed Oct 13, 2016.
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