Data collection
A pre- and post-intervention test on knowledge and attitudes about anaemia was conducted with participating adolescents before and after the education sessions. A structured pretested Knowledge Assessment Questionnaire with a maximum score of 18 was administered in Kannada. Post-intervention testing was conducted approximately 1-2 weeks after the last classroom session. In addition, post-intervention in-depth interviews (IDIs) with seven teachers and six focus group discussions (FGDs) with students, two in each district (one for girls and one for boys), were conducted to elicit information and opinions about how the intervention was carried out, including the strong and weak points of the educational methods used.

Data analysis

For quantitative data, descriptive statistics including means, standard deviations, percentages, and frequencies were used to illustrate respondents’ characteristics and intervention participation. Pre- and post- knowledge scores were calculated, and paired t-tests were used to determine significant changes in knowledge scores after the implementation of the intervention. The score obtained was also categorized as low (score between 0–5), medium (score between 6–11), and high (score between 12–18). Statistical analyses were done using the statistics programme STATA 17.0 (www.stata.com). Qualitative data was analysed using an inductive thematic approach. Transcripts were read by team members to develop separate coding framework for FGDs and IDIs, based on the topic guides. Coded sections were reviewed to generate themes, and team discussions were held to cross-check findings.