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 α=0.71 for the full and α=0.73 for the short version). The mean score (± standard deviation) 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

From the full set of questions available in the Claim Evaluation Tools item bank, we selected items referring to the Key Concepts that were considered eligible for high school students in the current health education model. Finally, a set of 18 items was included in the questionnaire. Each of the 18 MCQs consisted of a scenario leading to a treatment claim and a question with 3 or 4 possible answers. 

W created an online questionnaire using a Google Docs form. The form contained information about the scope of the study that students had to go through before answering questions. Completing the questionnaire was considered as consent for participation. The first part of the questionnaire included demographic data, like age, gender and the type of school participants attended. All answers from the test were automatically imported in an Excel file (Ver. Office 2007, Microsoft Corporation, Redmond, WA, USA).

We coded the answers and analysed the data using the SPSS v.24 (IBM Corp., Armonk, New York). 

We used descriptive statistics to present data from the test regarding the demographics, as well as frequencies of correct answers, and have presented those as absolute numbers and percentages for each test question. The overall test scores were presented using means (M) and standard deviations (SD).

For each question, we assessed gender differences using the MannWhitney test. Gender differences in the overall test results were analysed using the t-test for independent samples.

The variance of the overall test results regarding the type of school was assessed using the One-way ANOVA test. p<0.05 was considered statistically significant.

Least Significant Test (LSD) Fisher test was used for post-hoc analyses of the differences in the overall test scores between groups of female and male students in relation to the type of school.

Multiple regression analyses were performed to investigate the overall multivariate effect of the two variables, gender and the type of school, as well as to determine the level of individual contribution of each of these variables on the overall test results. 

The items from the Claim Evaluation Tools item bank are not publicly available, but access can be obtained from the IHC Project leaders upon request. The Supplementary file contains the list of Key Concepts of the questions selected for the Croatian test.