RESUMEN
AIM: There is an overabundance of claims about the advantages and disadvantages of health interventions. People need to be able to appraise the reliability of these claims. The aim of this two-arm cluster-randomized trial was to evaluate the Informed Health Choices secondary school intervention designed to teach students to assess claims about the effects of health actions and make informed decisions. METHODS: We conducted the trial among students from 80 secondary schools in five subcounties in Kenya. We used stratified randomization to allocate schools to the intervention or control arm. The intervention included a 2-day teacher training workshop and 10 lessons that addressed nine prioritized key concepts for assessing claims about treatment effects. We did not intervene in the control schools. The primary outcome was the proportion of students with a passing score (≥ 9/18 correct answers) on the Critical Thinking about Health test, which included two multiple-choice questions for each concept. RESULTS: Between May 11, 2022, and July 8, 2022, we recruited 3362 students and 80 teachers. We allocated 1863 students and 40 teachers to the intervention and 1499 students and 40 teachers to the control arm. In the intervention schools, 1149/1863 (61.7%) of students achieved a passing score compared to 511/1499 (34.1%) in the control schools (odds ratio 3.6 (95% CI 2.5-5.2), p < 0.0001). CONCLUSIONS: The intervention had a large effect on students' ability to think critically about health interventions. It is possible to integrate the learning of critical thinking about health within Kenya secondary school curriculum.