1.Ochr('39')Connor PO, Keogh IJ. Addressing human error within the Irish healthcare system. Irish Medical Journal. 2011;104(1):5-6. 2. Jahangiri M, Hoboubi N, Rostamabadi A, Keshavarzi S, Hosseini AA. Human error analysis in a permit to work system: a case study in a chemical plant. Safety and Health at Work. 2016;7(1):6-11. 3. Edmondson AC. Learning from mistakes is easier said than done: Group and organizational influences on the detection and correction of human error. JABS. 2004;40(1):66-90. 4. Makary MA, Daniel MJB. Medical error—the third leading cause of death in the US. Ninth International Congress On Peer Review And Scientific Pubulatio; 2016:1-5. 5. Zakerian SA, Najafi K, Fallahmedvari R, Jahangiri M, Jalilian H, Azimipoor RJOMQJ. Identification and assessment of human errors in the number of eye surgeries using PHEA technique. Occupational Medicine Quarterly Journal. 2017;9(3):1-13.[Persian] 6. Küng K, Carrel T, Wittwer B, Engberg S, Zimmermann N, Schwendimann R. Medication errors in a swiss cardiovascular surgery department: a cross-sectional study based on a novel medication error report method. Nursing Research and Practice. 2013;1-6. 7. Feyer A-M, Williamson AM, Cairns DR. The involvement of human behaviour in occupational accidents: errors in context. Saf. Sci. 1997;25(1-3):55-65. 8. Eyvazlou M, Dadashpour Ahangar A, Rahimi A, Davarpanah MR, Sayyahi SS, Mohebali Mal. Human reliability assessment in a 99Mo/99mTc generator production facility using the standardized plant analysis risk-human (SPAR-H) technique. JOSE. 2019;25(2):1-16. 9. Anderson JG, Jay SJ, Anderson M, Hunt TJ. Evaluating the impact of information technology on medication errors: a simulation. JAMIA. 2003;10(3):292-293. 10. Hollnagel EJC. Human reliability analysis: Context and control. 1st ed. London: Academic Press 1993:27-51. 11. Dhillon BS. Human reliability and error in transportation systems: Springer Science & Business Media; British: springer. 2007:29-41. 12. Kumar P, Gupta S, Agarwal M, Singh UJSs. Categorization and standardization of accidental risk-criticality levels of human error to develop risk and safety management policy. Saf. Sci. 2016;85:88-98. 13. Mohammadfam I, Saeidi C. Evaluating human errors in cataract surgery using the SHERPA technique. Iran J Ergon. 2015.2(4).41-47.[Persian] 14. Mohammadfam I, Mohammadi Y, Amiri M, Fallah Ksjjosp, Prevention I. Identifying and Prioritizing the Factors Affecting on the Human Errors in Health Care: Systematic Review. ICSP. 2018;6(2):87-90.[Persian] 15. Balas MC, Scott LD, Rogers AE. The prevalence and nature of errors and near errors reported by hospital staff nurses. Appl Nurs Res 2004;17(4):224-30. 16. Kohn LT, Corrigan J, Donaldson MS. To error is human: building a safer health system. 1st ed. USA: Washington, DC; National academy press 2000: 1-16. 17. Tevlin R, Doherty E, Traynor O. Improving disclosure and management of medical error–an opportunity to transform the surgeons of tomorrow. The Surgeon. 2013;11(6):338-43. 18. Khasha R, Sepehri MM, Khatibi T. A fuzzy FMEA approach to prioritizing surgical cancellation factors. IJHR. 2013;2(1):17-24. 19. Tait AR, Voepel-Lewis T, Munro HM, Gutstein HB, Reynolds P. Cancellation of pediatric outpatient surgery: economic and emotional implications for patients and their families. J Clin Anesth. 1997;9(3):213-9. 20. Mohammadfam I, Movafagh M, Soltanian A, Salavati M, Bashirian S. Assessment of human errors in the nursing profession of intensive cardiac care unit using SPAR-H method. Occupational Medicine Quarterly Journal. 2015;7(1):10-22.[Persian] 21. Ansari S, Choobdar M, Bakhtiari T, Jamalizadeh Z, heydari p, Varmazyar S. Identification and evaluation of human errors among Qazvin emergency medical personnel by using CREAM technique. Scientific journal of rescue and relief. 2018;10(1):98-110.[Persian] 22. Tanha F, Mazloumi A, Faraji V, Kazemi Z, Shoghi MJJoH. Evaluation of human errors using standardized plant analysis risk human reliability analysis technique among delivery emergency nurses in a hospital affiliated to Tehran University of Medical Sciences. journal of hospital. 2015;14(3):57-66.[Persian] 23. Stanton N. Hierarchical task analysis: Developments, applications, and extensions. Appl. Ergon. 2006;37(1):55-79. 24. U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research. The SPAR-H human reliability analysis method. Washington: 2005. 25. Laumann K, Rasmussen MJRE, Safety S. Suggested improvements to the definitions of Standardized Plant Analysis of Risk-Human Reliability Analysis (SPAR-H) performance shaping factors, their levels and multipliers and the nominal tasks. RELIAB ENG SYST SAFE. 2016;145:287-300. 26. Idaho National Laboratory(INL). SPAR-H step-by-step guidance. Washington: 2012. 27. Nazari T, Rabiee A, Ramezani A. Human Error Probability Quantification using SPAR-H Method: Total Loss of Feedwater case study for VVER-1000. Nuclear Engineering and Design. 2018; 331:295-301. 28. Rasekh R. Evaluation of Human Reliability by Standardized Plant Analysis Risk HRA (SPAR-H) method in the Dialysis Process in Ebne Sina Hospital, Shiraz. Iran J Ergon. 2019;7(3):44-56. 29. Pouya AB, Mosavianasl Z, Moradi-Asl E. Analyzing Nurses’ Responsibilities in the Neonatal Intensive Care Unit Using SHERPA and SPAR-H Techniques. Shiraz E Med J. 2019;20(6).1-9. Assessment of the probability of human error occurring in the process of appendectomy operation using SPAR-H method Taherzadeh Chenani KH1, Jahangiri M 2, Jafari Nodoushan R *3, Madadizadeh F 4, Fallah H5,6 1 Department of Occupational Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran 2 Department of Occupational Health Engineering, School of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran 3 Department of Occupational Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran 4 Research Center of Prevention and Epidemiology of Non-Communicable Disease, Department of Biostatistics and Epidemiology, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran 5 Department of Occupational Health Engineering, School of Health, Tabriz University of Medical Sciences, Tabriz, Iran 6 Occupational Health Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Abstract Introduction: The irreparable consequences of human error in the health care sector have made patient safety an important principle in medical professions. The aim of the present study was to investigate the probability of human error in operating room personnel in the process of appendectomy operations. Materials and Methods: This cross-sectional and descriptive study was performed to identify and evaluate the probability of human error in operating room personnelchr('39')s tasks in the process of appendectomy in Shahid Sadoughi Hospital in Yazd. Initially, by interviewing personnel and studying the process and procedures of the work, the job duties of the personnel were analyzed using HTA method. Finally, the probability of error was calculated using SPAR-H method for different tasks. Results: The average human error probability for all tasks was 0.173. Also, the highest mean of error was related to anesthesiologist duties (0.23) and the least related to scrub duties (0.101). Conclusion: The SPAR-H method can be used to analyze and quantify the probability of human error in the operating room. To reduce the likelihood of human error, we can reduce dependency by performing different tasks with different people and if possible with long time between them. Also, stress, complexity and procedures were identified as the most important factors affecting the probability of error.