About Nonfatal Injury Data

Types of Data

Nonfatal injury data from the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP), is available in the following WISQARS modules:

  • Injury Reports - Find tables of the total number of injury deaths and death rates, as well as national estimates of injuries treated in U.S. hospital emergency departments.
  • Injury Explore - Explore injury data presented in an interactive, visual format to easily identify populations at risk of fatal and nonfatal injuries.
  • Leading Causes of Nonfatal Injury - Visualize the ranking of leading causes of nonfatal injuries treated in U.S emergency departments.
  • Cost of Injury - Find the medical cost for injury deaths as well as cost associated with lives lost.
  • Infographics - Rapidly visualize fatal and nonfatal injuries in one summary page.

Where the data comes from

Nonfatal Data

The nonfatal injury data reported in WISQARS come from an expansion of the National Electronic Injury Surveillance System (NEISS) operated by the U.S. Consumer Product Safety Commission (CPSC). The expanded system, called the NEISS All Injury Program (NEISS-AIP), began on July 1, 2000, and collects data about all types and external causes of non-fatal injuries and poisonings treated in U.S. hospital emergency EDs–whether or not they are associated with consumer products.

The NEISS All Injury Program (NEISS-AIP) is a collaborative effort by the National Center for Injury Prevention and Control (NCIPC) and CPSC.

In 2019, CPSC began to redesign the NEISS sample to update the sampling frame. The redesign includes adding and replacing hospitals. The redesign includes a resample based on more recent hospital information from the American Hospital Association, including the list of hospitals by hospital type. The prior sample was drawn in 1997. In 2022, the NEISS-AIP sample increased to 79 hospitals from 56 hospitals in 2021. The NEISS-AIP sample goal is 100 hospitals; hospital recruitment and onboarding are ongoing. CPSC and CDC are continuing to release injury data while hospital recruitment is underway. CDC does not recommend using NEISS-AIP data for nonfatal firearm injury prevalence estimates at this time. Firearm injuries have distinct geographic patterns, and estimates can be imprecise or change over time when based on a small number of facilities. To ensure transparency in data reporting, WISQARS displays data on firearm injuries from years when the coefficient of variation from these estimates is <30. However, the wide confidence intervals indicate lack of precision for these estimates. Other systems used to assess nonfatal firearm injury trends include the National Syndromic Surveillance Program and the Healthcare Cost and Utilization Project. There is no current system that comprehensively measures all nonfatal firearm injuries in the US. Addressing this data gap is critical to inform action by public health and other community serving organizations.

Population Estimates

WISQARS's population estimates of the resident U.S. population are produced by the U.S. Census Bureau under a collaborative arrangement with CDC's National Center for Health Statistics (NCHS).

Please note that postcensal population estimates are updated annually, which means nonfatal injury rates from WISQARS may change slightly as denominators are updated.

Data collection methods

In the year 2000, NEISS collected information from a nationally representative sample of U.S. hospital emergency departments. The NEISS hospitals are a stratified probability sample of all U.S. hospitals (including U.S. territories) that have at least six beds and provide 24-hour emergency services. The NEISS-AIP data are collected from up to 100 hospitals each year, which represent the nation's range of hospital settings, including very large, large, medium, small, and children's hospitals.

What the data includes

The National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) hospitals provide data from about 500,000 injury-related emergency department (ED) cases yearly. Data from these cases are analyzed to provide national estimates on more than 20 causes of injury among different populations.

Users can search, sort, and view nonfatal injury data and create reports and charts based on the following:

  • Intent of Injury (unintentional injury, violence-related, assault, legal intervention, self-harm).
  • Mechanism (cause) of injury such as fall, fire, firearm, motor vehicle crash, poisoning, suffocation.
  • Disposition or where injured person goes when released from ED (treated and released, transferred, hospitalized, observed and left against medical advice).

How the data is interpreted

The following steps are followed to interpret the data:

  • Trained, onsite hospital coders take data for injury-related cases from ED records at NEISS hospitals.
  • The coders code all data elements, except for cause of injury.
  • These coded data and a narrative are entered into a computer and electronically transmitted to CPSC headquarters in Bethesda, MD.
  • NEISS-AIP quality assurance coders at CPSC headquarters receive data electronically and review all data elements as well as a narrative (description) for each case from each NEISS-AIP hospital.
  • Quality assurance coders then use the narrative and other data to assign codes for precipitating and direct causes of injury for each case.

The narratives, in most cases, provide enough detail about the circumstances of the injury event so that trained NEISS-AIP quality assurance coders could assign codes for cause of injury and confirm the intent of injury code assigned by the hospital coder.

NEISS hospital coders are trained not to interpret information provided in the ED record when writing the narrative but rather to transcribe exactly what medical providers recorded about the ED visit. Most narrative descriptions are based on doctors' and nurses' notes. This policy helps ensure that the data from the narrative is accurate and consistent.

In a joint effort, CDC and CPSC developed the coding guidelines for cause and intent of injury. The guidelines are consistent with coding guidelines in the International Classification of Disease-10th Revision (ICD-10). For more details about coding procedures, see the NEISS Coding Manual.

How the data benefits public health

Researchers, the media, federal, state, and local public health professionals, and the public can use WISQARS™ nonfatal data to:

  • Characterize and monitor nonfatal injuries trends.
  • Identify new or developing injury problems.
  • Identify persons at risk of nonfatal injuries.
  • Provide reliable surveillance data for program and policy decisions.

Data definitions

Nonfatal Injury

Bodily harm resulting from severe exposure to an external force or substance (mechanical, thermal, electrical, chemical, or radiant) or a submersion. This bodily harm can be unintentional, or violence related.

NEISS-AIP did NOT count an emergency department case as a nonfatal injury if:

  1. The principal diagnosis was an illness, pain only, psychological harm (such as anxiety or depression) only, contact dermatitis (skin irritation) associated with exposure to consumer products (such as body lotions, detergents, diapers) or plants (e.g., poison ivy).
  2. Pain symptoms were indicated in the ED record, but an injury-related diagnosis was NOT specified.
  3. The visit was for adverse effects of therapeutic drugs or of surgical and medical care; or
  4. The principal diagnosis was unknown.
  5. The patient died on arrival at the ED or during treatment in the ED.

Cost (Mechanism of Injury)

The cause, or mechanism, of injury is the way in which the person sustained the injury; how the person was injured; or the process by which the injury occurred. For this system, the cause of injury is the underlying cause, rather than the direct cause. The underlying cause is what starts the chain of events that leads to an injury. The direct is what produces the actual physical harm. The underlying and direct causes can be the same or different. For example, if a person cuts his or her finger with a knife, the cut is both the underlying and direct cause. However, if a child falls and hits his head on a coffee table, the fall is the underlying cause (the action that starts the injury event), and the contact with the table is the direct cause (the action that causes the actual physical harm).

NEISS-AIP uses the underlying cause rather than the direct cause of injury because the underlying cause is more important to prevention efforts. If we can prevent the underlying cause, we can stop the injury from occurring in the first place. In other words, without the underlying cause, there would be no direct cause. Reporting nonfatal injury data by the underlying cause of injury is consistent with how fatal injury data are reported. This way, users receive comparable fatal and nonfatal injury data for a specific cause (e.g., fall, poisoning, cut/pierce, etc.)

Cause of Injury Categories

BB/pellet gunshot: A penetrating force injury resulting from a BB, pellet, or other projectile shot from a BB or pellet gun (a compressed air or CO2-powered BB or pellet gun). This category includes gunshot wound from a bB or pellet rifle or pistol. This category does not include injury caused by a compressed air-powered paint gun or nail gun, which falls in the category "other specified."

Cut/pierce/stab: Injury resulting from an incision, slash, perforation, or puncture by a pointed or sharp instrument, weapon, or object. This category does not include injury from being struck by or against a blunt object (such as the side of a night stand) or bite wounds; these injuries fall in the category "struck by/against."

Dog bite: Injury caused by a dog bite. This category does not include injury from other animal bites.

Drowning/submersion: Suffocation (asphyxia) resulting from submersion in water or another liquid.

Fall: Injury received when a person descends abruptly due to the force of gravity and strikes a surface at the same or lower level.

Fire/burn/smoke inhalation: Severe exposure to flames, heat, or chemicals that leads to tissue damage in the skin or places deeper in the body; injury from smoke inhalation to upper airway, lower airway, or lungs.

Firearm gunshot: A penetrating force injury resulting from a bullet or other projectile shot from a powder-charged gun. This category does not include injury caused by a compressed air-powered paint gun or a nail gun, which falls in the “other specified” category.

Foreign body: Injury resulting from entrance of a foreign body into or through the eye or other natural body opening that does not block an airway or cause suffocation (asphyxia). Examples include pebble or dirt in eye, BB in ear, or small childrens' toys in esophagus.

Inhalation/ingestion/suffocation: Inhalation, aspiration, or ingestion of food or other object that blocks the airway or causes suffocation; intentional or accidental mechanical suffocation due to hanging, strangulation, lack of air in a closed place, plastic bag or falling earth. This category does not include injury resulting from a foreign body that does not block the airway (see foreign body).

Machinery: Injury that involves operating machinery, such as drill presses, fork lifts, large power-saws, jack hammers, and commercial meat slicers. This category does not include injury involving machines not in operation, falls from escalators or moving sidewalks, or injuries from powered lawn mowers or other powered hand tools or home appliances.

Natural / environmental: Injury resulting from exposure to adverse natural and environmental conditions (such as severe heat, severe cold, lightning, sunstroke, large storms, and natural disasters) as well as lack of food or water.

Other bite / sting: Injury from a poisonous or non-poisonous bite or sting through the skin, other than a dog bite. This category includes human bite, cat bite, snake or lizard bite, insect bite, stings from coral or jellyfish, or bites and stings by other plants and animals.

Other specified causes: Injury associated with any other specified cause that does not fit another category. Some examples include causes such as electric current, electrocution, explosive blast, fireworks, overexposure to radiation, welding flash burn, or animal scratch.

Overexertion: Working the body or a body part too hard, causing damage to muscle, tendon, ligament, cartilage, joint, or peripheral nerve (e.g., common cause of strains, sprains, and twisted ankles). This category includes overexertion from lifting, pushing, or pulling or from excessive force.

Poisoning: Ingestion, inhalation, absorption through the skin, or injection of so much of a drug, toxin (biologic or non-biologic), or other chemical that a harmful effect results, such as drug overdoses. This category does not include harmful effects from normal therapeutic drugs (i.e., unexpected adverse effects to a drug administered correctly to treat a condition) or bacterial illnesses.

Struck by / against or crushed: Injury resulting from being struck by (hit) or crushed by a human, animal, or inanimate object or force other than a vehicle or machinery; injury caused by striking (hitting) against a human, animal, or inanimate object or force other than a vehicle or machinery.

Transportation-related causes: Injury involving modes of transportation, such as cars, motorcycles, bicycles, and trains. This category is divided into four subcategories according to the person injured: motor vehicle occupant, motorcyclist, pedal cyclist, pedestrian, and other transport. This category also involves another factor–whether the injury occurred in traffic (on a public road or highway).

Unknown/unspecified cause: Injury for which the emergency department report does not provide enough information to describe the cause of injury.

Subcategories of Transportation-Related Causes

Motor vehicle occupant: Injury to a driver or passenger of a motor vehicle caused by a collision, rollover, crash or some other event involving another vehicle, an object, or a pedestrian. This category includes occupants of cars, pickup trucks, vans, heavy transport vehicles, buses, and SUVs. Injuries to occupants of other types of vehicles such as ATVs, snowmobiles, and go-carts fall in the category of "other transport."

Motorcyclist: Injury to a driver or passenger of a motorcycle resulting from a collision, loss of control, crash, or some other event involving a vehicle, object, or pedestrian. This category includes drivers or passengers of motorcycles (classic style), sidecars, mopeds, motorized bicycles, and motor-powered scooters.

Other transport: Injury to a person boarding, alighting, or riding in or on all other transport vehicles involved in a collision or other event with another vehicle, pedestrian, or animal not described above. It includes railway, water, air, space, animal and animal-drawn conveyances (e.g., horseback riding), ATVs, battery-powered carts, ski lifts, and other cable cars not on rails.

Pedal cyclist: Injury to a pedal cycle rider from a collision, loss of control, crash, or some other event involving a moving vehicle or pedestrian. This category includes riders of unicycles, bicycles, tricycles, and mountain bikes. This category does not include injuries unrelated to transport (moving), such as repairing a bicycle.

Pedestrian (struck by or against a vehicle): Injury to a person involved in a collision, where the person was not at the time of the collision riding in or on a motor vehicle, railway train, motorcycle, bicycle, airplane, streetcar, animal-drawn vehicle, or other vehicle. This category includes persons struck by cars, pickup trucks, vans, heavy transport vehicles, buses, and SUVs. This category does not include persons struck by other vehicles such as motorcycles, trains, or bicycles; these cases fall in the category of "other transport."

Another Factor (Data Element) for Transportation-Related Causes: Traffic

This factor (data element) applies only to the five transport-related causes (motor vehicle occupant, motorcyclist, pedal cyclist, pedestrian, and other transport). For cases involving at least one of these transport-related causes, WISQARS notes whether the injury occurred in traffic (i.e., on a public road or highway). Specifically, the categories for this data element include traffic-related, not traffic-related, and unknown / unspecified:

Traffic-Related: Any vehicle incident occurring on a public highway, street, or road (i.e., originating on, terminating on, or involving a vehicle partially on the highway). All events that involved a motor vehicle crash (i.e., collision involving a car, pickup truck, heavy truck, or SUV) are considered traffic related, even if the report doesn't specify traffic relatedness.

Events that involved motorcycles, ATVs, go-carts, and other off-road vehicles, are not considered traffic related. Also, boarding and alighting injuries fall into the category of unknown/unspecified unless the report noted the injuries occurred in traffic.

Non-traffic: Any vehicle incident that occurs entirely in any place other than a public highway, street, or road.

Unknown / unspecified: Any vehicle incident that is not a motor vehicle crash and that did not have a report specifying whether the incident happened on a public highway, street, or road.

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