Safety event class	Level of harm	Harm category	Patient description
HI—Harmful incident (reaches the patient)
Harm results from the care or services provided to the patient due to failures in the processes of care or in the performance of procedures, including provider error Based on expert opinion	DE—Death	HI–DE	Unexpected death not related to the natural or expected course of the patient’s illness or underlying condition. On balance of probabilities, caused by or brought forward by the incident
	SE—Severe	HI–SE	Patient harm is symptomatic: • requiring life-saving intervention or major medical/surgical intervention, • shortening life expectancy, or • causing major temporary or permanent impact on physical, mental or social function • patient experienced enduring psychological difficulty that required specialist treatment (e.g. prolonged counselling and psychotropic medication management) Includes previous catastrophic disability
	MO—Moderate	HI–MO	Patient harm is symptomatic: • requiring intervention (e.g. additional operative procedure, additional therapeutic treatment), and increased length of stay, or • causing temporary or permanent impact on physical, mental, or social function • patient experienced psychological difficulty requiring treatment (e.g. counselling with FP, therapist, or psychologist)
	MI—Mild	HI–MI	Patient harm is symptomatic: • symptoms are mild • minimal or no intervention is required (e.g. extra observation, investigation, review, or minor treatment) • causing minimal (permanent or temporary) impact on physical, mental, or social function • patient experienced emotional distress that had an impact on lifestyle (e.g. mild sleep disturbances, occasional work absences)
	NO—None†	HI–NO	Patient harm is asymptomatic. No symptoms detected and no treatment required
	ID—Insufficient detail	HI–ID	• Insufficient information is available to evaluate the level of harm • There may be no description of any clinical outcome • There may be a patient safety incident but insufficient information to classify level of harm of the outcome
IR—Inherent risk (reaches the patient)
A known risk associated with a particular investigation, medication, or treatment. It is the risk from undergoing a procedure in ideal conditions, performed by qualified staff using current standards, equipment and techniques* Includes non-preventable missed or delayed diagnosis Based on expert opinion	DE—Death	IR–DE	Unexpected death not related to the natural or expected course of the patient’s illness or underlying condition. Caused by or brought forward as a result of the inherent risk of the care
	SE—Severe	IR–SE	Patient harm is symptomatic: • requiring life-saving intervention or major medical/surgical intervention, • shortening life expectancy, or • causing major temporary or permanent impact on physical, mental or social function • patient experienced enduring psychological difficulty that required specialist treatment (e.g. prolonged counselling and psychotropic medication management) Includes previous catastrophic disability
	MO—Moderate	IR–MO	Patient harm is symptomatic: • requiring intervention (e.g. additional operative procedure, additional therapeutic treatment), and increased length of stay, or • causing temporary or permanent impact on physical, mental, or social function • patient experienced psychological difficulty, requiring treatment (e.g. counselling with FP, therapist, or psychologist)
	MI—Mild	IR–MI	Patient harm is symptomatic: • symptoms are mild • minimal or no intervention is required (e.g. extra observation, investigation, review, or minor treatment) • causing minimal (permanent or temporary) impact on physical, mental, or social function • patien t experienced emotional distress that had an impact on lifestyle (e.g. mild sleep disturbances, occasional work absences)
	NO—None†	IR–NO	Patient harm is asymptomatic. No symptoms detected and no treatment required. Includes persistence of condition (e.g. myopia, carpal tunnel)
	ID—Insufficient detail	IR–ID	• Insufficient information is available to evaluate the level of harm • There may be no description of any clinical outcome • There may be a patient safety incident but insufficient information to classify level of harm of the outcome
UN—Unknown (reaches the patient)
Harm results from the care or services provided to the patient, but no expert opinion on file to categorize as harm arising from a harmful incident or inherent risk Usually involves cases with a contributing factor of UNKNOWN			Level of patient harm is not populated due to limited information on the file
NM—Near miss
A patient safety incident that did not reach the patient and therefore no harm results	No—None	NM–NO	Error or capacity to cause harm was caught by an error detection barrier, or by chance, before reaching the patient
No healthcare-associated harm occurred	Level of harm	Harm category	Patient description
NA-not applicable		NA	Involves all other medical-legal matters that are solely administrative (e.g. documentation) or related conduct (e.g. manner)