Tehran University of Medical Sciences Journal of Medical Ethics and History of Medicine 2008-0387 12 0 2019 03 06 464 464 EN Mohammad Mohammadi PhD Candidate in Medical Ethics, Medical Ethics and History of Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Medical Ethics, School of Medicine, Tehran, University of Medical Sciences, Tehran, Iran; Faculty of Medicine, Department of Medical Ethics, Mashhad University of Medical Sciences, Mashhad, Iran. Bagher Larijani Professor, Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Seyed Mahmoud Tabatabaei Professor, Medical Ethics and History of Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran. Saharnaz Nedjat Professor, Knowledge Utilization Research Center, Tehran University of Medical Science, Tehran, Iran; Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Masud Yunesian Professor, Department of Research Methodology and Data Analysis, Institute for Environmental Research, Tehran University of Medical sciences, Tehran, Iran; Department of Environmental Heath, School of Public Health, Tehran University of Medical sciences, Tehran, Iran. Fatemeh Sadat Nayeri Professor, Maternal-Fetal and Neonatal Research Center, Tehran University of Medical Sciences, Tehran, Iran. 2018 09 02 2019 03 06 Medical errors are among the major challenges that threaten patients’ health worldwide. The aim of this study was to design a valid and reliable questionnaire to investigate the status of medical error disclosure by physicians. A preliminary questionnaire was developed based on the extracted results from 37 interviews with specialists. To test the validity of the questionnaire, 20 medical practitioners and medical ethics authorities were asked to evaluate the relevance and clarity of each item. To measure the instrument’s reliability (the intra-class correlation coefficient and Cronbach’s alpha), a test-retest study was conducted on 20 randomly selected physicians twice with a 2-week interval. Statistical analyses were performed using SPSS software version 20.  The overall relevance and clarity of the instrument, with an average approach, were measured at 97.22 and 94.03 percent respectively. The Cronbach’s alpha, which presents the internal consistency was satisfactory (0.70 - 0.79) for various domains of the questionnaire. The range of intra-class correlation coefficients for the items in all domains of the questionnaire was 0.76 to 1.00. Regarding the validity and reliability of the questionnaire, it can be an appropriate instrument in the assessment and monitoring of the status of medical error disclosure by physicians. https://jmehm.tums.ac.ir/index.php/jmehm/article/view/464 https://jmehm.tums.ac.ir/index.php/jmehm/article/download/464/293