Avedis Donabedian was the first to propose and use a tool to measure patient safety back in 1960s. The Donabedian triad of structure, processes and outcome are still very much relevant when measuring patient safety and healthcare quality. Currently there are numerous tools that are used to measure patient safety and medication error. The IHI Global trigger tool is one of the widely used tools. The link to the Global trigger tool is: https://psnet.ahrq.gov/resources/resource/5248
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Radhwan M. Hussein who validated this questionnaire?
Habib Alrashedi I would go for the Survey on Patient Safety Culture issued and validated by AHRQ. You can find all details online under the name HSOPSC.
For the hospital context, the most widely used system is the NCCMERP index (https://www.nccmerp.org/types-medication-errors). This index categorize the severity of medication errors. Its reliability has been well studied [ Pharmacoepidemiol Drug Saf. 2007 Sep;16(9):1006-13. ; Am J Health Syst Pharm. 2007 Jan 15;64(2):175-81. ].
For the ambulatory context (community pharmacy), the DOCUMENT system has been succesfully used for projects studying drug related problems in the Pharmacy Guild of Australia [Int J Clin Pharm. 2012 Feb;34(1):43-52. doi: 10.1007/s11096-011-9583-1. Epub 2011 Nov 19. ]. Or, the SCOPE criteria which were derived from the very original version of the NCCMERP index. Their reliability and validity was established for CKD care [ Am J Health Syst Pharm. 2015 Nov 1;72(21):1876-84. doi: 10.2146/ajhp140765],