Definitions for Nonfatal Injury Reports

This section provides definitions of data elements and specific categories within data elements available from WISQARS nonfatal injury reports. The data elements in the main report options are cause of injury; traffic-relatedness; intent of injury; sex,  age, and disposition of the patient; and year of reporting.   Some of these elements are made up of categories, which also are defined below.  The advanced report options address age groups, age adjusting, advanced statistics, and sorting by race/ethnicity, age, age group, and sex.

Some of these options are made up of subcategories and additional data elements, which also are defined below.

5.2.1 Data Element: Cause ( 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 cause 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).

This system 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).

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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.

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 the 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 includes gunshot wounds from powder-charged handguns, shotguns, and rifles. 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.

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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.”

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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, the system 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). If a report did not specify traffic relatedness and the event involved a motor vehicle crash (i.e., collision involving a car, pickup truck, van, heavy truck, or SUV), this system assumed the event was traffic-related; this policy is consistent with ICD-9-CM coding rules.4.  If a report without specification involved motorcycles, ATVs, go-carts, and other off-road vehicles, this system did not assume the event was traffic-related. Also, boarding and alighting injuries fall into the category of unknown/unspecified unless the report noted the injuries occurred in traffic.

(For more information about data sources and the process of obtaining and coding data for WISQARS, see help file Data Sources)

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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5.2.2 Data Element: Intent of Injury

Intent of Injury: Whether an injury was caused by an act carried out on purpose by oneself or by another person(s), with the goal of injuring or killing.

Note: This system categorized cases of unknown or undetermined intent as unintentional injuries. However, expanding the definitions of assault and intentional self harm to include confirmed and suspected cases minimized the numbers of cases with unknown or undetermined intent. For most cases, the report indicated intent (or lack of intent) to harm.

Intent of Injury Categories

Assault, confirmed or suspected: Injury from an act of violence where physical force by one or more persons is used with the intent of causing harm, injury, or death to another person; or an intentional poisoning by another person. This category includes perpetrators as well as intended and unintended victims of violent acts (e.g., innocent bystanders). This category excludes unintentional shooting victims (other than those occurring during an act of violence), unintentional drug overdoses, and children or teenagers “horsing” around.

For assaults, NEISS-AIP collects data about the relationship of the perpetrator to the injured person (such as spouse, partner, parent, other relative, friend, stranger, or multiple perpetrators) and the context of the assault (such as altercation, robbery, sexual assault, drug-related, gang-related, and drive-by shooting).

Assault – other: This category includes a majority of the assaults and excludes cases where the reason for the assault was classified as sexual assault (as defined below). If the emergency department record did not indicate that the assault involved sexual assault, then it was coded as other assault.

Assault – sexual:  An assault as defined above that also involves

  • Completed or attempted penetration of a victim
  • Completed or attempted acts in which a victim is made to penetrate a perpetrator or someone else

(Penetration involves physical insertion, however slight, of the penis into the vulva; contact between the mouth and the penis, vulva, or anus; or physical insertion of a hand, finger, or other object into the anal or genital opening of another person.)

  • Unwanted sexual contact: intentional touching, either directly or through the clothing, of the genitalia, anus, groin, breast, inner thigh, or buttocks of any person without his or her consent. Unwanted sexual contact can be perpetrated against a victim or by making a victim touch the perpetrator.

All sexual assault involves a lack of freely given consent including situations in which the victim is:

  • Unable to consent because of the victim’s age, illness, mental or physical disability, being asleep or unconscious, or being too intoxicated (e.g., incapacitation, lack of consciousness, or lack of awareness) through their voluntary or involuntary use of  alcohol or other drugs; or
  • Unable to refuse because of  the use or possession of guns or other non-bodily weapons, or due to physical violence, threats of physical violence,  intimidation or pressure, or misuse of authority.

This category includes rape, completed or attempted; sodomy, completed or attempted; and other sexual assaults with bodily force or when the victim is unable to consent, completed or attempted.

Assault and legal:  This category includes all assault cases AND all legal intervention cases.

Legal intervention: Injury or poisoning caused by police or other legal authorities (including security guards) during law enforcement activities. Includes injuries and poisonings (mace, pepper spray) inflicted during legal action or execution, or while attempting to enforce the law such as arrest or restraint of arrested persons.

Self-harm, confirmed or suspected: Injury or poisoning resulting from a deliberate violent act inflicted on oneself with the intent to take one’s own life or with the intent to harm oneself. This category includes suicide, suicide attempt, and other intentional self-harm.

Unintentional: Injury or poisoning that is not inflicted by deliberate means (i.e., not on purpose). This category includes those injuries and poisonings described as unintended or “accidental”, regardless of whether the injury was inflicted by oneself or by another person. Also, includes injury or poisoning where no indication of intent to harm was documented in the ED record.

Violence-related:  Injury or poisoning inflicted by deliberate means (i.e., on purpose).  This category includes the assault, legal intervention, and self-harm categories.


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5.2.3 Data Element: Race / Ethnicity

Definition: Race or Hispanic origin of the patient as recorded on the emergency department (ED) record. On the ED record, often only one entry is available for race or ethnicity. The classification scheme for this system assumes that most white Hispanics probably were recorded on the ED record as Hispanics, and most black Hispanics probably were recorded as black. The four categories include white, non-Hispanic; black (including Hispanic and non-Hispanic); Hispanic (for all races other than black); and unknown/unspecified.

Requesting nonfatal injury data by race and ethnicity
WISQARS Nonfatal does not offer the option to request leading causes of injury by race/ethnicity because of the relatively high percentage of cases (i.e., approximately 17%) with unknown race / ethnicity. On the nonfatal injury report request page, you can request the number of injuries from a specific cause and intent of injury by race / ethnicity categories by selecting “race” as a sort option . Please note that annualized national estimates presented for each race/ethnicity category will be low because they do not count cases recorded as “unknown” race/ethnicity.


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5.2.4 Data Element: Sex

Sex: Gender of the patient as recorded on the emergency department record. The three possible categories are male, female, and unknown / undetermined.


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5.2.5 Data Element: Age

Age: Age in years of the patient at the time of treatment, as recorded on the emergency department record. WISQARS Nonfatal gives age in years; “0” indicates less than 1 year, while 85 represents 85 years and older.


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5.2.6 Data Element: Disposition

Disposition: The status of the injured person at the time of release from the emergency department. The five possible categories are treated and released; transferred to another facility (e.g., trauma center, rehabilitation unit); transferred and hospitalized; hospitalized; and observed (i.e., held for observation) or unknown.


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5.2.7 Data Element: Year of Reporting

Year of Reporting: The year in which the patient was treated in a U.S. hospital emergency department.


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5.2.8 Advanced Report Options

Advanced report options allow you to further tailor the report you request to your information needs.  The advanced options include age categories, age adjusting, advanced statistics, and sorting.

Age Categories

WISQARS provides three ways to select the age-range for a report:

  • All Ages (default), which includes those of unknown age.
  • Specific Age Ranges, which allows you to choose a specific age-range in 5-year increments (periods). This selection permits you to limit the age-range of your request and still have age-adjusted rates. If you want a report on a single 5-year age group, both fields should contain the same value (e.g., 0-4 to 0-4).
  • Custom Age Range, which allows you to choose a specific age range of any increment.  However, you cannot obtain age-adjusted rates with a custom age range.

Note: Age ranges include the ages specified in the range. For example, the age range 15-19 includes those who are 15 years old and those who are 19 years old. Also, note that population estimates are not available for a single year-of-age for all standard years. Therefore, WISQARS Nonfatal does not perform age adjusting for custom ranges.


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Age Adjusting: Some injuries occur more often among certain age groups than others.  For instance, falls are more common among the elderly than among any other age group. Age adjustment enables you to compare injury rates without concern that differences are because of differences in the age distributions between different populations or for the same population over time.

Because of the way age-adjusted rates are computed, WISQARS Nonfatal may not be able to display age-adjusted rates for all categories on a report. For instance, a report by sex will have age-adjusted rates for males and for females, not both sexes combined. If you need an age-adjusted rate for both sexes, a second request is required. Also, because of the way age-adjusted rates are computed, you cannot get age-specific rates and age-adjusted rates at the same time. If you selecting a report sorted by Age Group AND choose a standard year for age-adjusting, WISQARS will ignore the request for age-adjusted rates.


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Advanced Statistics: WISQARS nonfatal injury reports offer advanced statistics for public health professionals or others familiar with these measures; they are NOT intended for the general public.

When you request advanced statistics, you will receive summary statistics related to the stability of the national estimates the system computes. In addition to the national estimate, population, crude rate and age-adjusted rate, this option provides data on the number of records used to compute the national estimate, the standard error (SE), the coefficient of variation (CV),  and the lower and upper 95% confidence limits. The CV is a measure of relative standard error and is computed as SE/national estimate. The SE also is  used to calculate the 95% confidence limits, computed as the national estimate ± 1.96 (SE). The 95% confidence limits is a standard measure of stability when estimates are based on sample data. The SE is computed using a variance estimation procedure that uses the sample weights and accounts for the stratified sample design (i.e., four strata defined by hospital size based on the number of emergency department visits annually and one stratum of children’s hospitals) of the NEISS All Injury Program. WISQARS considers a national estimate unstable when 

  • the estimate is less than 1,200
  • or the number of records used is less than 20, or
  • the CV exceeds 30%.


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Sorting: This option allows you to request a report that includes separate nonfatal injury data for various groups (age group, age, race/ethnicity, sex and year). For example, if you request sort by sex, then the report will separate the data by male and female. You can select up to four attributes, and the order in which you select them will affect the report.

For example, if you request a report to be sorted by age group and sex for national estimates of nonfatal injuries, the report will appear in the following form:


 Age Group  Sex Number of
Population Crude
00-04 Both Sexes 2,470,783 18,907,931 13,067.44
Males 1,439,260 9,684,355 14,861.70
Females 1,030,251 9,223,576 11,169.76
Unknown 1,272*
05-09 Both Sexes 2,119,246 19,901,031 10,648.92
Males 1,258,504 10,199,319 12,339.10
Females 860,422 9,701,712 8,868.76
Unknown 320*
10-14 Both Sexes 2,594,960 20,081,462 12,922.17
Males 1,624,177 10,290,387 15,783.44
Females 969,807 9,791,075 9,905.01
Unknown 976*
15-19 Both Sexes 3,228,199 19,758,190 16,338.53
Males 1,995,428 10,123,573 19,710.71
Females 1,232,102 9,634,617 12,788.28
Unknown 668*



The same report ordered by sex and age group would produce the following result:


Age Group Number of
Population Crude
Both Sexes 00-04 2,470,783 18,907,931 13,067.44
05-09 2,119,246 19,901,031 10,648.92
10-14 2,594,960 20,081,462 12,922.17
15-19 3,228,199 19,758,190 16,338.53
Unknown 6,956*
Males 00-04 1,439,260 9,684,355 14,861.70
05-09 1,258,504 10,199,319 12,339.10
10-14 1,624,177 10,290,387 15,783.44
15-19 1,995,428 10,123,573 19,710.71
Unknown 4,052*
Females 00-04 1,030,251 9,223,576 11,169.76
05-09 860,422 9,701,712 8,868.76
10-14 969,807 9,791,075 9,905.01
15-19 1,232,102 9,634,617 12,788.28


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5.2.9 Crude Rate

The crude rate identifies the number of injuries one would find among 100,000 people of that population.  For instance, there were approximately 135,000,000 males in the US in 2000.  If there were 1,350  injuries in a particular category, the crude rate would be  1,350 / 135,000,000 * 100,000 =  1.0 per 100,000 population.

WISQARS Nonfatal Injury Reports