Background: Randomized trials underpin important healthcare decisions. A challenge that evidence producers face is that people without formal training may have difficulty understanding good design principles or interpretation of the evidence. Primary or secondary school may be an opportunity to teach basic concepts of randomized study designs.
Objective: To teach middle school students about trial design and use evidence to determine whether KitKats sold in the USA or those sold in the UK are 'better'.
Methods: To prepare for the class exercise, we removed KitKats from their wrapping, divided bars into 5.25 g morsels, and covered them in aluminum foil to mask the candy. Classes included students enrolled in three 8th grade science classes at a Baltimore public school. We started with a discussion of how to conduct a fair test. We randomized students to two groups: those assigned to consume USA KitKats first and those to consume UK KitKats first. Students drank a cup of water as a 'wash-out' before consuming the alternate candy. Using paper forms, students assigned each candy three separate scores for freshness, chocolate-iness, and deliciousness, using a Likert scale from 1 (lowest) to 5 (highest).
Results: Sixty-three students and 12 facilitators participated. On average, students favored USA KitKats, rating them as fresher, more chocolatey and more delicious than UK KitKats, irrespective of treatment sequence. During the exercise, we discussed why students could not choose which KitKat to eat first (randomization), why the candies were wrapped in foil (masking), why they needed water between KitKats (washout) and how to define 'better' (outcomes). Despite our attempt at masking, some students noticed differences in logos and color.
Conclusion: Follow-up discussion with the classroom teacher verified that this interactive exercise helped students understand the principles of conducting a randomized trial. Strengthening students’ abilities to recognize reliable research and the potential for using trials to test treatments contributes towards sharing knowledge and minimizing challenges to evidence-based healthcare.