| Age-Adjusted Rate | 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... ] |
| Age-Specific Rate | 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. Also known as an age-specific fertility rate. |
| Age-Specific Death Rate | The number of resident deaths in a specific age group per 100,000
population in the age group. |
| Apgar Score | 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. |
| Artifact | An artifact is any representation in data, such as observational or data entry errors, that would
cause one to misinterpret the results. |
| Birth | 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 Defect | 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
chromosomal anomalies." |
| Birthweight | The first weight of the newborn obtained after delivery. Birthweight is recorded in grams. |
| Cause of Death Classification | 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 | 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... ] |
| Confounding Variable | 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.
|
| Count | 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... ] |
| Crude Rates | A crude rate is a rate that has not been adjusted for artifacts
or confounding variables, such as the age and sex composition of a
population. [ more... ] |
| Crude Birth Rate | The number of resident births per 1,000 population (male and female). |
| Crude Death Rate | The number of resident deaths per 100,000 population. |
| Feeding at Discharge | The type of feedings (breast, formula, or both) given in the 24 hours prior to discharge
from the hospital. |
| Fetal Death | A fetal death is death prior to the complete expulsion or extraction from its mother
of a product of conception, irrespective of the duration of pregnancy and which is not an
induced termination of pregnancy. The death is indicated by the fact that after such
expulsion or extraction, the fetus does not breathe or show any other evidence of life
such as 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. Induced terminations of pregnancy (ITOPs) are not included in fetal death reporting.
In New Jersey health data reports, fetal death refers only to spontaneous fetal deaths.
Fetal death data for New Jersey can be produced using the
Custom Fetal Death Query section of the NJSHAD Website. |
| 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. |
| ICD Codes | 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. The U.S. began using the 10th revision (ICD-10) to record
cause of death on death certificates on January 1, 1999 and to record diagnoses on medical records on October 1, 2015. |
| Incidence | The number of cases of disease having their onset during a prescribed period of time. |
| Infant Death | 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 data for New Jersey
can be produced using the
Custom Infant Death Query section of the NJSHAD Website. |
| 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 (IMR) | The number of resident deaths under one year of age in a given year per 1,000
births in the same year. |
| Intercensal Population Estimates | Population estimates produced for the years between two decennial censuses when
both the beginning and ending populations are known. They are produced once a decade
by adjusting the existing time series of postcensal estimates for the
entire decade to smooth the transition from one decennial census count to the next.
They differ from the postcensal estimates that are released annually because they
rely on a mathematical formula that redistributes the difference between the April 1 postcensal estimate and
April 1 census count for the end of the decade across the estimates for that decade. For dates when both
postcensal and intercensal estimates are available, intercensal estimates are preferred. |
| Parity | The number of previous live-born children a woman has delivered. |
| Percent Change | 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 |
| Perinatal Mortality | 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. |
| Plurality | Singleton, twin, triplet, quadruplet, etc. |
| Population Estimates | Population estimates are used as denominators in the calculation of public health rates.
The best source of population estimates for the state and counties by age, sex, race, and/or
Hispanic origin is the U.S. Census Bureau's Population Estimates Program (PEP). PEP also
produces total population estimates for municipalities but the American Community Survey
must be used if demographic characteristics are needed for county subdivisions. |
| Postcensal Population Estimates | Population estimates produced for the years after a decennial census when only the
beginning population is known. They are produced and revised each year. For dates when both postcensal and
intercensal estimates are available, intercensal estimates are preferred. |
| Postneonatal Mortality | 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. |
| Prevalence | The number of cases of a disease, number of infected people, or number of people with some other attribute present during a particular interval of time. |
| Primary Cesarean | 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. |
| Rate | 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... ] |
| Repeat Cesarean | 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
previous cesarean. |
| Reliability | 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
small populations,
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... ] See also
NCHS. |
| Relative Standard Error | A measure of an estimate’s reliability. [ more... ] |
| Small Numbers | "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 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. |
| Statistic | 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.
|
| 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 | 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. |
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