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5.0 Data
Sources for WISQARSTM
Nonfatal
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
5.2 The
National Electronic Injury Surveillance System (NEISS)
5.3
Type of Data Captured and Coding Methods in NEISS-AIP
5.4
Population Estimates
5.5
National Estimates: Statistical Reliability and Seasonality
5.6
Availability of New Data
5.7
Citing Data Presented by WISQARS
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5.1
Purpose and Intended Audience of WISQARS Nonfatal
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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
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5.2
The National Electronic Injury Surveillance System (NEISS)
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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
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5.3
Type of Data Captured and Coding Methods in NEISS-AIP
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5.3.1 Data
Captured
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.
5.3.2 Coding
Methods
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
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5.4
Population Estimates
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Population figures are new bridged-race postcensal population estimates of the resident population of the United States for April 1, 2000, July1, 2001, and July 1, 2002. 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 population estimates for 2000 and 2001 have been updated, which means that nonfatal injury rates obtained using WISQARS prior to September 1, 2003 may be different.
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5.5
National Estimates: Statistical Realiability and
Seasonality
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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. National estimates for 2001 were computed using
data from January through December of that year--a full year
of data.
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%.
These
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.
5.5.2
National Estimates and Seasonality
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.
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5.6
Availability of New Data
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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. Nonfatal injury data will be updated in September/October 2004 with national estimates based on data obtained for the calendar year 2003. After that, data will be updated annually about 10-11 months after the end of each calendar year.
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5.7
Citing Data from WISQARS Nonfatal
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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].
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