This help file section provides a detailed description of the purpose of and data sources for WISQARS Nonfatal as well as the procedures involved in processing the data. The topics include
5.1 Purpose and Intended Audience of WISQARS Nonfatal
WISQARS Nonfatal provides data from the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP). This data is intended for a broad audience--the public, the media, public health practitioners and researchers, and public health officials--to increase their knowledge of nonfatal injury. The NEISS-AIP data provides information about what types of nonfatal injuries occur in U.S. hospital emergency departments, how common they are, who they affect, and what causes them. In addition, the NEISS-AIP data help federal, state, and local public health officials to
- characterize and monitor trends in non-fatal injuries,
- identify emerging injury problems,
- identify persons at risk, and
- provide reliable surveillance data for program and policy decisions.4
5.2 The National Electronic Injury Surveillance System (NEISS)
The nonfatal injury data used in WISQARS Nonfatal are obtained 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 departments (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.
Since May 1971, CPSC has used NEISS to monitor consumer product-related injuries in its regulatory jurisdiction. In the year 2000, NEISS collected information from a nationally representative sample of 100 U.S. hospital EDs. 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 at 66 of the 100 NEISS hospitals, which represent the nation's range of hospital settings. NEISS and NEISS-AIP hospitals include very large inner-city hospitals with trauma centers as well as large urban, suburban, rural, and children's hospitals.3
5.3 Type of Data Captured and Coding Methods in NEISS-AIP
The National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) hospitals will provide data from about 500,000 injury-related emergency department (ED) cases yearly. Data from these cases are weighted by the inverse of the probability of selection to provide national estimates.
In addition to the age, race/ethnicity, sex, and disposition ( where injured person goes when released from ED); cause/mechanism of injury; and intent of injury, data are being collected about the principal diagnoses, primary body part affected, locale where the injury occurred, and whether the injury is related to work.
For transportation-related injuries, NEISS-AIP collects data about whether the injury was related to traffic and the status of the motor vehicle occupant (e.g., driver, passenger, and boarding or alighting) when the injury occurred.
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).
Only part of these data elements are available currently in
WISQARS-NFI (see section 4.0 for
data elements available and their definitions). The
additional data will be provided through a third WISQARS
Nonfatal section, which is presently in planning stages.
The additional data will help further characterize and
describe nonfatal injuries in the U.S.
Trained, onsite hospital coders took data for injury-related cases from ED records at NEISS hospitals. The coders coded all data elements, except for cause of injury. These coded data and a narrative were entered into a computer and electronically transmitted to CPSC headquarters in Bethesda, MD. NEISS-AIP quality assurance coders at CPSC headquarters received the data electronically and reviewed all of the data elements as well as a narrative (description) for each case from each of the 66 NEISS-AIP hospitals. Quality assurance coders then used the narrative and other data to assign codes for precipitating and direct causes of injury for each case.
The narratives, in most cases, provided enough detail about the circumstances of the injury event so that trained 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 (ICD) 9-CM.5,6 For more details about coding procedures, see the NEISS Coding Manual.7
Population figures are new bridged-race postcensal population estimates of the resident population of the United States for April 1, 2000 for the census year, and July1 for the postcensal years. These estimates were produced by the Population Estimates Program of the U.S. Census Bureau under a collaborative arrangement with the National Center for Health Statistics (NCHS). Theses estimates are consistent with population estimates used by NCHS for calculating mortality rates based on data from the National Vital Statistics System. For more information about these population data, visit the National Center for Health Statistics website at www.cdc.gov/nchs/about/major/dvs/popbridge/popbridge.htm. Please note that postcensal population estimates are updated annually, which means that nonfatal injury rates from WISQARS prior to the update may be different.
5.5.1 National Estimates and Statistical Reliability
The number of nonfatal injuries presented in WISQARS Nonfatal are national estimates based on weighted data from the U.S. Consumer Product Safety Commission's (CPSC) National Electronic Injury Surveillance System (NEISS). Because data collection for the NEISS All Injury Program did not begin until July 2000, national estimates for 2000 were computed using data obtained from July through December of that year. A full year data (January 2001 - December 2001)was used for computing national estimates for 2001 and later years
For 2000, the overall national estimate of nonfatal injuries is based on approximately 230,000 NEISS cases, making the national estimate very reliable. However, 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. These potentially unstable estimates are identified with a red asterisk (*). 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%.
criteria are similar to those recommended by CPSC for national
estimates of consumer product-related injuries. You can
view these statistical criteria when you request a nonfatal
injury report by selecting "advanced
statistics." For more information, visit the
WISQARS Nonfatal tutorial.
Comparing national estimates of nonfatal injuries for 2000 with those for 2001 and later years is not recommended. Because data collection for the NEISS All Injury Program did not begin until July 2000, national estimates for 2000 were computed using data obtained from July through December of that year. These estimates may be subject to the effects of seasonality—that is, for any given injury cause, the estimate may reflect differences in the number injuries that occur during certain times of year. For example, if more bicycle injuries occur during summer and early fall, the 2000 estimate for bicycle injuries would be higher than it would have been if the estimates were calculated for a full year of data. National estimates for 2001 and later years, on the other hand, were computed using data from January through December of those years; they are not subject to the effects of seasonality.
5.6 Availability of New Data
The nonfatal injury data reported on NCIPC web pages come from the National Electronic Injury Surveillance System All Injury Program (NEISS-AIP). NEISS-AIP began on July 1, 2000, and will continue indefinitely. Currently, annualized national estimates for 2000 are based on data from July 1 through December 31, 2000. Annualized estimates for 2001 and later years are based on data from January 1 through December 31 of that year. We plan to update Nonfatal injury data each September/October with national estimates from the prior calendar year data. After that, data will be updated annually about 10-11 months after the end of each calendar year.
To cite the results from WISQARSTM in papers and other presentations, use the following text:
Centers for Disease Control and Prevention. Web-based Injury Statistics Query and Reporting System (WISQARS) [Online]. (2003). National Center for Injury Prevention and Control, Centers for Disease Control and Prevention (producer). Available from: URL: www.cdc.gov/ncipc/wisqars. [Year Month (abbreviated) Day--this is the date you accessed the data].