An age-adjusted rate is a rate that controls for age effects, allowing better
comparability of rates across geographic areas. Age-adjustment may also be used to control for age
effects when comparing across several years of data, as the age distribution of the population
changes over time. [ more... ]
An age-specific rate is a rate in which both the numerator (number of events)
and denominator (number in population at risk) are limited to a specific age group.
It is calculated by dividing the total number of health events for the specific age group of
interest by the total population in that age group. [ more... ]
Age-Specific Birth Rate
The number of resident births to females in a specific age group per 1,000
females in the age group.
Age-Specific Death Rate
The number of resident deaths in a specific age group per 100,000
population in the age group.
A summary measure of an infant's clinical condition based on heart rate, respiratory
effort, muscle tone, reflex irritability, and color taken at one and five minutes after delivery. Each of
the factors is given a score of 0, 1, or 2; the sum of these five values is the Apgar score which can
range from 0 to 10. A score of 10 is optimal and a low score (usually considered to be less than 7) is
considered an indication of potential health problems and raises concerns about the subsequent
health and survival of the infant.
An artifact is any representation in data, such as observational or data entry errors, that would
cause one to misinterpret the results.
A birth is the complete expulsion or extraction from its mother of a product of conception,
irrespective of the duration of pregnancy, which, after such separation, breathes or shows any
evidence of life, such as beating of the heart, pulsation of the umbilical cord, or definite
movement of voluntary muscles. Births are sometimes referred to as live births. Birth data
for New Jersey can be produced using the
Custom Birth Query section of the NJSHAD Website.
Birth defects include cleft lip/palate, club foot, spina bifida, Down syndrome, and
other problems that happens while the baby is developing in the mother's body.
Birth defects are also referred to as "congenital malformations, deformations, and
The first weight of the newborn obtained after delivery. Birthweight is recorded in grams.
A system of specification of the diseases and/or injuries which led to
death and the sequential order of their occurrence. The version of the system in use since 1999 is the
International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-
10), sponsored by the World Health Organization.
Cause-Specific Death Rate
A cause-specific death rate is the number of resident deaths from a specific cause per 100,000 population.
Cause-specific death rates can be crude or age-adjusted rates.
Confidence interval lower limit.
Confidence interval upper limit.
The confidence interval may be thought of as the range of probable true values for a
statistic. In general, as a population or sample size increases,
the confidence interval gets smaller. Estimates with smaller confidence intervals are referred
to as more "precise." Less precise estimates, such as those calculated from
small numbers, tend to have wide confidence intervals.
Typically, the 95% confidence interval (calculated as 1.96 times the standard error of a statistic)
indicates the range of values within which the statistic would fall 95% of the time if
the researcher were to calculate the statistic (e.g., a percentage or rate) from an infinite
number of samples of the same size drawn from the same base population.
[ more... ]
A confounding variable is a variable that is related to, and may obscure one's view of, the
variable of interest. For instance, when examining death rates across populations, the population's
age distribution can be a confounding variable because higher death rates will be found in populations
with a greater proportion of persons in older age groups. In such a case, one could use an
age-adjusted rate to compare the populations.
A count is the number of health events, such as a death or a reported disease incident, that
occurred within a specified time period. [ more... ]
The first weight of the fetus obtained after delivery. Delivery weight is recorded in grams.
Significant differences in the overall rate of disease incidence, prevalence, morbidity,
mortality, or survival rates between one population and another.
[ more... ]
Feeding at Discharge
The type of feedings (breast, formula, or both) given in the 24 hours prior to discharge
from the hospital.
A fetal death is death prior to the complete expulsion or extraction from its mother
of a product of conception; the fetus shows no signs of life such as breathing or beating
of the heart, pulsation of the umbilical cord, or definite movement of voluntary muscles.
Fetal deaths are also referred to as stillbirths, miscarriages, or spontaneous abortions.
New Jersey law requires the reporting of all fetal deaths of 20 or more weeks gestational
age. An induced termination of pregnancy (ITOP) is a kind of fetal death, however ITOPs
are reported separately from spontaneous fetal deaths. In New Jersey health data reports,
fetal death refers only to spontaneous fetal deaths.
Fetal Mortality Rate
The number of resident fetal deaths of 20 or more weeks gestation per 1,000
resident live births plus fetal deaths of 20 or more weeks of gestation. (This rate is
often referred to as Fetal Death Rate.)
First Birth Rate
Determined from the sum of number of births now living plus number of (live) births
now dead stated on the birth certificate. If either of these is not stated, the sum is
considered not stated. For those whose sum equals zero (i.e., first births), rates are
computed per 1,000 female population.
The number of resident births per 1,000 females aged 15-44 years.
The clinical estimate of the length of time from the first day of the mother's last normal
menstrual period to the date of delivery.
ICD is the acronym for "International Classification of Diseases." It is a
coding system maintained by the World Health Organization and the U.S. National Center for
Health Statistics used to classify causes of death on death certificates and diagnoses, injury
causes, and medical procedures for hospital and emergency department visits. These codes are
updated every decade or so to account for advances in medical technology. Beginning in 1999,
the U.S. changed over from the 9th revision (ICD-9) to the 10th revision (ICD-10) to record
cause of death on death certificates.
An infant death is death within the first year of life. An infant must be live-born to
be considered an infant death, otherwise it is a fetal death.
Infant Death Rate
The number of resident deaths under one year of age per 1,000 population. (The
infant death rate is usually not reported by the New Jersey Department of Health
and is often used interchangably with Infant Mortality Rate.)
Infant Mortality Rate
The number of resident deaths under one year of age in a given year per 1,000
births in the same year.
The marital status of the mother for statistical purposes is determined for data years
after 1988 by the response to the birth certificate item, "Mother married? (At birth,
conception, or any time between)".
Individual births in twin, triplet, quadruplet, and higher order multiple deliveries.
NCHS Leading Causes
In order to provide a consistent ranking standard the National Center for Health Statistics (NCHS)
prepared a list of 113 selected causes of death for use with ICD-10. The 33 major cause of death groups
are taken from the list of 113. For more information about the NCHS rankings, see Cause of Death Ranking
on the NCHS website. Leading causes of death for New Jersey can be calculated using the
Custom Mortality Query
section of the NJSHAD Website. [ more... ]
Death of an infant within the first 27 days of life.
Neonatal Mortality Rate
The number of resident infant deaths within the first 27 days of life per 1,000
An inclusive term used to represent data which are missing, unknown, not available, or
The number of previous live-born children a woman has delivered.
The difference between the new number, rate, or percentage and the old number,
rate, or percentage divided by the old number, rate, or percentage multiplied by 100:
(new - old)/old * 100
Definition I: The sum of fetal deaths occurring after 28 or more weeks of gestation
plus infant deaths occurring less than seven days after live birth.
Definition II: The sum of fetal deaths occurring after 20 or more weeks of gestation
plus infant deaths occurring less than 28 days after live birth.
Only spontaneous fetal deaths, not induced or intentional terminations of
pregnancy, are included in this definition. (The age range used for perinatal mortality
varies between reports and between organizations. Use care when comparing.)
Perinatal Mortality Rate
Definition I: The number of resident fetal deaths of 28 or more weeks gestation plus
infant deaths occurring less than seven days after live birth per 1,000 resident
live births plus fetal deaths of 28 or more weeks of gestation.
Definition II: The number of resident fetal deaths of 20 or more weeks gestation plus
infant deaths occurring less than 28 days after live birth per 1,000 resident
live births plus fetal deaths of 20 or more weeks of gestation.
Singleton, twin, triplet, quadruplet, etc.
Death of an infant from 28 days to one year of life.
Postneonatal Mortality Rate
The number of resident infant deaths from 28 days to one year of life per
1,000 live births.
Cesarean delivery of a woman who has never had a cesarean before.
Primary Cesarean Rate
The number of cesarean deliveries per 100 births to women who have not
had a previous cesarean.
A rate is a fraction, in which the numerator is the number of people among whom an event
occurred during a certain period of time, and the denominator is the total number of people
in the population at risk for the same period of time. Rates are typically multiplied by some
factor of ten so that the result is a whole number. [ more... ]
Cesarean delivery of a woman who has had one or more prior cesareans.
Repeat Cesarean Rate
The number of cesarean deliveries per 100 births to women who have had a
Reliability is a property of a measurement that refers to its precision, or the degree to
which observations of identical phenomena yield identical results. In public health, we often
use measures such as death rates or birth outcomes to indicate the true underlying risk of
illness or disability in a population. Often such measures, when observed in
are said to yield "unreliable results" because the observations tend to vary considerably over
time. That fluctuation makes them an unreliable measure of the true underlying population risk.
[ more... ]
"Small numbers" is a term that is used to denote a population or a survey sample that is relatively
small, yielding imprecise estimates for the health event of interest. "Small" is defined differently
for different purposes, but in general, populations that yield 20 or fewer health events in the
specific time period are generally considered small. Even for complete count datasets,
such as birth and death certificate datasets, random fluctuations over time will yield estimates that are
not reliable. For instance, the death rate for a short time period from a small population will not
reflect the true underlying death risk for that population. The precision of an estimate
may be indicated by the confidence interval for the estimate. As
the population size decreases, the confidence interval widens, indicating less precision, or less
"confidence" with regard to how well the estimate reflects the true underlying risk in that population.
A statistic is a number that summarizes data. A descriptive statistic summarizes data in
a limited or bounded dataset. Examples include the average age of students in a class and the
percentage of employees who purchased dependent health coverage. An inferential statistic
summarizes data in a sample drawn from a larger population, of which the sample is intended
to be representative. Statistics calculated from the sample are used to make inferences about
the population, and are typically accompanied by a confidence
interval, used to suggest the precision of the statistic. Examples include the percentage
of youth in a survey who smoked cigarettes or the average body mass index among sampled persons.
Age-specific birth rates of women in five-year age groups multiplied by five and
summed to form a total for all ages. This rate indicates the number of children a cohort of 1,000
women would bear if they experienced the existing age-specific birth rates throughout their
A trend is a view of multiple years of data so rate changes over time can be analyzed.
A trend is often shown as a simple line graph so that the trend is easily
visible. Due to the changing age distribution of the population (i.e., the "aging" of the population
over time) it is useful to use age-adjusted rates to compare rates
over several years.
Trimester of Pregnancy
The first trimester includes the first 12 weeks of pregnancy, the second
trimester encompasses the thirteenth through twenty-fourth weeks and the third trimester is the period
after the twenty-fourth week through delivery.
Underlying Cause of Death
The underlying cause of death is the disease or injury which initiated the chain of events
leading directly to death or the circumstances of the unintentional injury or violence which
produced the fatal injury. All cause-of-death data in NJSHAD relate to the underlying
cause of death coded from the death certificate unless otherwise noted.
Unintentional injuries include motor vehicle-related injuries, poisonings,
falls, burns and smoke inhalation, drowning, suffocation, and other injuries.
Unintentional injuries are commonly referred to as "accidents."
Vaginal Birth After Previous Cesarean (VBAC)
Vaginal delivery of a woman who has previously had a cesarean delivery.
Vaginal Birth After Previous Cesarean (VBAC) Rate
The number of vaginal births after previous cesarean (VBAC) deliveries per
100 births to women with a previous cesarean delivery.
Validity is a property of a measurement that refers to its accuracy, or the degree to
which observations reflect the true value of a phenomenon. In public health, we are
lucky because the validity of most of our measures is really quite good. "Cause of death"
on death certificates is certified by a physician. Survey measures have been tested to
maximize validity. Birthweight is measured and reported at the birth hospital. There are
some measures that we question, for instance self-reported body weight, but on the whole,
the measures we use have a high degree of validity. [ more... ]
Very Low Birthweight
Birth weight of less than 1,500 grams or approximately 3 pounds, 5 ounces.
The weighted average, or weighted mean, is an average in which the data elements have been
differentially weighted. Data elements with a high weight contribute more to the weighted
average than do elements with a low weight. If all data components in the calculation have
the same weight, it is called the arithmetic mean. In the case of
age-adjusted rates for health events, a weighted mean is used
to adjust, or age-standardize, health event rates for two or more populations with different
The information provided above is from the New Jersey Department of Health's
NJSHAD Web site (http://nj.gov/health/shad). The information published
on this website may be reproduced without permission. Please use the following citation:
"Retrieved Sat, 18 May 2013 22:08:30
from New Jersey Department of Health, Center for Health Statistics,
State Health Assessment Data Web site: http://nj.gov/health/shad".