OBJECTIVES: We validated the Croatian version of the test using multiple-choice questions (MCQs) from the Claim Evaluation Tools item bank of the Informed Health Choices project, and measured the ability of high school students to appraise health claims. SETTING: 16 high schools from the urban agglomeration of the city of Split, Croatia. PARTICIPANTS: Final year high school students of at least 18 years of age. INTERVENTIONS: 18 MCQs from the item bank considered relevant for high school students were translated. After face-validity testing, the questionnaire was piloted and sent to a convenient sample of 302 high school students. PRIMARY AND SECONDARY OUTCOME MEASURES: Difficulty and discrimination indices were calculated for each MCQ to determine the validity of translation and the weight of MCQs. We assessed basic metric characteristics and performed initial validation of the test. Two tests were created, the full (18 MCQs) and the short version (12 MCQs). We analysed differences in test score according to gender and school. RESULTS: The response rate was 96% (75% female respondents). Metric characteristics of both tests were satisfactory (Cronbach's α=0.71 for the full and α=0.73 for the short version). The mean score (±SD) for the full version was 11.15±3.43 and 8.13±2.76 for the short version. There were 6 easy and 12 moderately difficult questions. Questions concerning effectiveness and dissimilar comparison groups were answered correctly by fewer than 40% of students. Female students and those from grammar and health schools scored higher on both tests. CONCLUSIONS: Both tests showed good metric characteristics and may be used for quick and reliable assessments of adolescents' ability to appraise health claims. They may be used to identify needs and inform development of educational activities to foster critical thinking about health among adolescents.
