The findings of this study are published in: Purić, D., Petrović, M. B., Živanović, M., Lukić, P., Zupan, Z., Branković, M., Ninković, M., Lazarević, L. B., Stanković, S., & Žeželj, I. (2023). Development of a novel instrument for assessing intentional non-adherence to official medical recommendations (iNAR-12): A sequential mixed-methods study in Serbia. *BMJ Open, 13*(6), e069978. https://doi.org/10.1136/bmjopen-2022-069978. Please cite accordingly.