Assertion-evidence slides appear to lead to better comprehension and recall of more complex concepts

In a sampling of several thousand slides from engineering and science, almost two-thirds had a topic-phrase headline supported by a bulleted list of subtopics.1 Because slides are used so often by engineering educators to communicate research, to teach students, and to have students demonstrate what they have learned, the question arises how effective this topic-subtopic structure is, compared with other slide structures, for helping audiences understand and remember the information. This paper compares students' learning from a presentation that relies on this commonly used topic-subtopic slide structure versus students' learning from a presentation that follows an assertion-evidence slide structure. In the assertion-evidence structure, the heading is a succinct sentence assertion and the body of the slide supports that heading with visual evidence. Theoretically, from communication and cognitive psychology perspectives, the assertion-evidence slide structure should be more effective at fostering student learning. In the experiment, two audiences heard the same recorded presentation, but one audience (55 participants) viewed topic-subtopic slides and another (56 participants) viewed assertion-evidence slides. The presentation, which took about 6 minutes to view, explained the process of how magnetic resonance imaging can detect cancerous tumors. Both sets of students were tested immediately after the presentation and then again about one week later. On the questions testing for comprehension and retention of more complex concepts, students learning from the assertion-evidence slides scored higher than did students learning from topic-subtopic slides. These higher scores (some of which achieved statistical significance) occurred on both the essay test given immediately afterwards and the multiple choice test given one week later. What might be most important here is that those learning from topic-subtopic slides did not score significantly higher than those learning from assertion-evidence slides. In other words, even though learners of topic-subtopic slides viewed markedly more written information during the presentation, those learners did not understand and remember more of that written information. That finding is important because using assertion-evidence slides has additional benefits. In particular, theory says that a presenter creating a talk with an assertion-evidence approach will create a more focused and overall stronger presentation than that same presenter using a topic-subtopic approach.