Killed or Seriously Injured
Killed or Seriously Injured (KSI) is a standard metric for safety policy, particularly in transportation and road safety.
United Kingdom definitions
- Killed: The usual international definition, as adopted by the Vienna Convention in 1968 is 'A human casualty who dies within 30 days after the collision due to injuries received in the crash'.
- Serious injury: The definition is less clear-cut a may vary more over time and in different places. The UK definition covers injury resulting in a person being detained in hospital as an in-patient, in addition all injuries causing: fractures, concussion, internal injuries, crushings, burns (excluding friction burns), severe cuts, severe general shock which require medical treatment even if this does not result in a stay in hospital as an in-patient.
- Slight injury: Sprain (including neck whiplash injury), bruising or cuts which are not judged to be severe. Also slight shock requiring roadside assistance.
United States definitions
The definitions used in the USA are as follows:
- Fatal injury. To be used where death occurs within thirty consecutive 24-hour time periods from the time of the crash.
- Incapacitating injury. Any injury, other than a fatal injury, which prevents the injured person from walking, driving or normally continuing the activities the person was capable of performing before the injury occurred. This includes: severe lacerations, broken or distorted limbs, skull or chest injuries, abdominal injuries, unconsciousness at or when taken from the crash scene, and unable to leave the crash scene without assistance. Does not include momentary unconsciousness.
- Non-incapacitating evident injury: Any injury, other than a fatal injury or an incapacitating injury, which is evident to observers at the scene of the crash in which the injury occurred. This includes: lump on head, abrasions, bruises and minor lacerations. This does not include limping unless any actual injury can be seen.
Figures for fatalities are normally highly reliable in industrialised countries and few if any fatalities go unrecorded. Fatality figures are however often too low making it hard to see trends over time for one place.
Figures for the number of people seriously injured typically being an order of magnitude larger than the number of people killed and are therefor more likely to be statistically significant. However, classification of serious injuries is open to opinion, by medical staff or by non-medical professionals, such as police officers and may therefore vary over time and between places.
Figures for slight injuries are considered highly unreliable, largely due to under-reporting where injuries are self-treated.
- "Progress towards the 2010 targets". Parliament. "Human casualties who sustain injuries leading to death less than 30 days after the accident. (This is the usual international definition, adopted by the Vienna Convention in 1968"
- "Progress towards the 2010 targets". Parliament. "An injury for which a person is detained in hospital as an 'in- patient', injury or any of the following injuries whether or not they are detained in hospital: fractures, concussion, internal injuries, crushings, burns (excluding friction burns), severe cuts, severe general shock requiring medical treatment and injuries causing death 30 or more days after the accident. An injured casualty is recorded as seriously or slightly injured by the police on the basis of information available within a short time of the accident. This generally will not reflect the results of a medical examination, but may be influenced according to whether the casualty is hospitalised or not. Hospitalisation procedures will vary regionally."
- "Progress towards the 2010 targets". Parliament. "An injury of a minor character such as a sprain (including neck whiplash injury), bruise or cut which are not judged to be severe, or slight shock requiring roadside assistance. This definition includes injuries not requiring medical treatment."
- "FARS coding and validation manual" (pdf).
- iRAP International Transport Statistics Database :: Safety: Data Definitions and Caveats