WISQARS Glossary

Injury Outcomes

ED Treated and Release: Refers to patients treated for an injury in a United States hospital emergency department and then released without being hospitalized or transferred for specialized physical or psychological care. Secondary emergency department visits related to the same injury incident are not included in this category. The source of the data used to estimate the number of such visits is NEISS-AIP.

Fatal: Refers to injury-related deaths for which a death certificate was filed in a state vital statistics office and then submitted to the National Center for Health Statistics for inclusion in the National Vital Statistics System.

Hospitalization: Refers to patients initially treated for an injury in a United States hospital emergency department and then either hospitalized or transferred for specialized physical or psychological care. Patients directly admitted to a hospital from outpatient clinics or other treatment venues, and patients treated and released from hospital emergency departments are excluded from this category. Secondary hospitalizations related to the same injury incident are also excluded. The source of the data used to estimate the number of injury-related hospitalizations is the National Electronic Injury Surveillance System – All Injury Program (NEISS-AIP).

Injury Intents

All Intents: This grouping combines all injury intent categories. For injury-related deaths, it also includes injuries due to operations of war (which are not separately reportable).

Unintentional: This category refers to fatal and nonfatal injuries not deliberately inflicted, including any such injury described as an "accident," regardless of whether inflicted by oneself or by another person. Injuries resulting in hospitalization subsequent to ED treatment or resulting in ED treatment only, and for which intent was not determined, are also included in this category as most such injuries were likely unintentional.

Homicide/Assault: This category refers to fatal and nonfatal injuries due to acts of violence where physical force by one or more persons is used with the intent of causing harm, injury, or death to another person. Such injuries resulting in hospitalization subsequent to ED treatment or resulting in ED treatment only are reportable under the categories assault-other and assault-sexual, which include confirmed and suspected cases based on patient medical records.

Legal Intervention: This category refers to fatal and nonfatal injuries caused by police or other law enforcement agents in the course of official duties. For injury-related deaths this category includes state-sanctioned executions.

Suicide/Self-harm: This category refers to fatal and nonfatal injuries resulting from deliberate self-directed violence. For injuries resulting in hospitalization subsequent to ED treatment or resulting in ED treatment only, the self-harm category includes confirmed and suspected cases based on patient medical records.

Undetermined: This category is separately reportable only for injury-related deaths. It refers to instances in which the intent of injury was not determined. Injuries resulting in hospitalization subsequent to ED treatment or resulting in ED treatment only, and for which the intent was not determined, are included in the unintentional category.

Unintentional: This category refers to fatal and nonfatal injuries not deliberately inflicted, including any such injury desrcribed as an "accident," regardless of whether infliected by oneself or by another person. Injuries resulting in hospitalization subsequent to ED treament or resulting in ED treatment only, and for which intent was not determined, are also included in this category as most such injuries were likely unintentional.

Statistics

Age-Adjusted Rate: WISQARS calculates the age-adjusted rate by multiplying the crude rate by a standard weight for each particular age group. Age adjustment allows us to compare injury rates without concern that differences in those rates are caused by variations in the age distributions between populations or among the same population over time. When reports are requested for all ages in a particular population, WISQARS automatically calculates age-adjusted rates, unless you choose otherwise. However, for reports requested by standard age groups and custom age ranges, only crude rates per 100,000 are available. The method used to calculate age adjustment does not allow WISQARS to compute age-adjusted rates by age groups.

Age-Adjusted YPLL Rate: The years of potential life lost per 100,000 people, adjusted for differences in 5-year groupings. The age-adjusted YPLL rate allows accurate comparisons between different age groups. This measure is calculated by multiplying each 5-year age range's YPLL rate by the proportion of people in that age-range.

Crude Rate: WISQARS figures the crude rate per 100,000 by dividing the number of deaths or injuries in a particular population by the total number of people in that population, then multiplying that ratio by 100,000.

Crude YPLL Rate: The years of potential life lost per 100,000 people. This measure is calculated by summing all the years of potential life lost, dividing by the total population, and then multiplying this value by 100,000.

Years of Potential Life Lost (YPLL): A measure of premature mortality (early death). For a given cause category, WISQARS calculates the years lost before age 65 (YPLL-65) through two steps. First, the system subtracts each deceased person's age at death from 65. Next, the system adds the results — the "years lost"– for all deceased people in that category. WISQARS Fatal allows you to change the standard age from 65 to other ages in five-year increments up to age 85 (e.g., 70, 75, 80, 85).

Cost Types

Lifetime Medical Costs: Medical care cost estimates are important to monitor the economic burden of injuries and help to prioritize cost-effective public health prevention activities. Existing comprehensive estimates of medical care cost for injuries by injury type were calculated using primarily hospital-based data.

Quality of Life Lost Costs: The quality-adjusted life year (QALY) is a measure of disease or injury burden that captures both the quality and the duration of life lived post disease or injury. QALYs, either monetised or unmonetised, are used in studies of injury costs and of treatment and prevention benefits from many perspectives, including those of society, of victims and their families, and of the healthcare system, when analysing its ability to cost-effectively produce and preserve health.

Value of Statistical Life: A monetary estimate of the collective value placed on mortality risk reduction as derived in research studies through revealed preferences or stated preferences from surveys of individual persons' willingness to pay for mortality risk reduction.

Work Loss Costs: Estimates of lost work productivity—sometimes called an indirect cost, as distinct from the direct cost of medical care for injuries—attributable to injuries are important to monitor the economic burden of injuries and help to prioritise cost-effective prevention activities.

Suppression Notations

Fatal Data

For rare injuries and/or for small populations, a rate might be based on a very small number of deaths. When the total number of deaths used to calculate any rate (crude, age-adjusted, or smoothed) is fewer than 20, the rate is considered statistically unstable. States or counties with unstable rates are displayed using a cross-hatch pattern in maps.

Any unstable rate will at a minimum be annotated as such, and in some instances will be suppressed entirely. All rates based on one to nine deaths will be suppressed. If a rate is based on greater than nine deaths but fewer than twenty deaths, it is considered unstable.

** indicates unstable value (<20 deaths)

-- indicates suppressed value (between one to nine deaths)

--* indicates secondary suppression (value suppressed to prevent derivation of suppressed values)

Non-fatal Data

The number of nonfatal injuries presented in WISQARS are national estimates based on weighted data from the U.S. Consumer Product Safety Commission's (CPSC) National Electronic Injury Surveillance System (NEISS). When you request detailed tables by specific causes/mechanisms of injury and intents of injury by age, sex and/or race/ethnicity, some national estimates may be based on relatively few cases and therefore unstable. The statistical criteria used to flag these national estimates are:

computation, based on fewer than 20 NEISS cases (based on unweighted data)
national estimates less than 1,200 (based on weighted data), or
the coefficient of variation (CV) of the estimate greater than 30%.

These criteria are similar to those recommended by CPSC for national estimates of consumer product-related injuries.

-- indicates suppressed value (based on <20 unweighted count, <1,200 weighted count, or coefficient of variation of the estimate >30%)

--* indicates secondary suppression (value suppressed to prevent derivation of suppressed values)