How the design of presentation slides affects audience comprehension: A case for the assertion-evidence approach

Engineering educators often create slides for classroom presentations to instruct students. In turn, engineering students often create slides for classroom presentations to demonstrate what they have learned. Given how often presentation slides are projected and viewed by engineering educators and students, those slides should follow principles of multimedia learning to foster high audience comprehension. Unfortunately, Microsoft PowerPoint, which is the dominant program for creating slides, does not incorporate these principles into its defaults. As a result, most educators and students in engineering create slides that violate these principles. To determine the effect of this violation, we compared learning outcomes in 110 engineering students who viewed a technical presentation in which the slides either integrated or violated six multimedia learning principles. The presentation slides that adhered to the six multimedia principles followed the assertion-evidence approach, while the presentation slides that violated the six multimedia principles followed commonly practiced defaults of PowerPoint. Essay responses from the 110 engineering students revealed superior comprehension and fewer misconceptions for the assertion-evidence group as well as lower perceived cognitive load. In addition, stronger recall occurred in this assertion-evidence group at delayed post-test. These findings support the use of the assertion-evidence structure for presentations in engineering education.