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Technical Notes

Registration

New York State consists of two registration areas, New York City and New York State exclusive of New York City. New York City includes the five counties of Bronx, Kings (Brooklyn), Queens, New York (Manhattan) and Richmond (Staten Island); the remaining 57 counties comprise New York State exclusive of New York City. The Bureau of Production Systems Management, New York State Department of Health, processes data from live birth, death, fetal death and marriage certificates recorded in New York State exclusive of New York City. Through a cooperative agreement, the Department of Health receives data on live births, deaths, fetal deaths and marriages recorded in New York City and on live births and deaths recorded outside of New York State to residents of New York State. The Bureau of Production Systems Management processes data from dissolution of marriage certificates recorded in New York State.

Residence

Except for marriages and dissolution of marriages, which are classified by county of occurrence, all the vital statistics presented in this report are based on the vital records of events to New York State residents. The events are allocated to the place of usual residence as reported on the certificates, with one exception. Vital events occurring to inmates of state and federal institutions within the first year of their incarceration are allocated to their residence at the time of admission. After one year, the institution then becomes the place of residence. Vital events occurring to resident staff are allocated to the institution district.

Events occurring to residents of communities neighboring major metropolitan areas are sometimes misallocated. In areas where postal boundaries and civil divisions do not coincide, the mailing address is sometimes misreported as the place of residence. Analysis involving small geographic areas should be conducted with awareness of this potential problem.

Live Births

New York State Public Health Law (§ 4130) defines a live birth as 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 other evidence of life such as beating of the heart, pulsation of the umbilical cord or definite movement of voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached.

The selection of race for the statistical reporting of live births is based upon the race of the mother only. Prior to 1991, the reporting of the infant's race was based on the race of both the mother and father.

Ethnicity, separate from race, is based on the ethnicity of the mother. Prior to 1991, the reporting of the infant's ethnicity was based on the ethnicity of the mother and father. Due to an expanded specificity in the reporting of ethnicity in 1993, a substantial increase in the number of infants with unknown ethnicity was observed. Ethnicity distinguishes individuals of Spanish origin, where the Hispanic category includes Hispanic Whites, Hispanic Blacks, Hispanics of Other Races and Hispanics-race not stated.

Early prenatal care is defined as prenatal care during the first trimester of the pregnancy. Late prenatal care is defined as prenatal care during the third trimester of the pregnancy. Beginning with 1993 live births, the method of determining when prenatal care began changed. For 1993 and subsequent years, the month in which prenatal care began is determined by calculating the interval between the date of last normal menses and the date of the first prenatal visit. This calculation is consistent with the calculation of gestational age. Previously, the month of the pregnancy in which prenatal care began was reported on the certificate. This change in the method for determining when prenatal care began has resulted in a significant shift toward a later start of prenatal care. The statistical shift may not reflect an actual change in practice.

The New York State and New York City late or no prenatal care data in 1999 should be interpreted with caution. The data shifted markedly from 1998 due to increased quality assurance activities conducted by the New York City Office of Vital Statistics. As a result of these efforts, the number of records with missing information on the question of trimester for first prenatal visit declined dramatically. Reports on each level of prenatal care increased, especially reports of no care.

The categories used for reporting the method of delivery of live births include vaginal, cesarean and other. "Other" method includes vaginal breech, outlet forceps, mid and low forceps, and vacuum.

Attendant at birth is categorized as physician, midwife or other. Physician includes medical doctors and doctors of osteopathy. Midwife includes certified nurse midwives and midwives.

The number of out of wedlock live births is imputed. New York State Public Health Law (§ 4135) prohibits the specific statement on the birth certificate as to whether the child was born in wedlock or out of wedlock. Prior to 1977, the marital status was inferred by examining statistical information on the certificate of live birth. In 1977, the procedure was modified to also identify out of wedlock live births when a paternity affidavit was filed, births that were previously identified as being in wedlock. This modification resulted in a noticeable increase in the estimated number of out of wedlock live births. Beginning in 1993, out-of-state recorded live births to New York State residents no longer have paternity affidavits filed with them.

Deaths

The cause of death reported in this publication is the underlying cause classified according to the tenth revision of the International Classification of Diseases (ICD, 10th revision) adopted by New York State in 1999. Historically, several revisions of the ICD have been used, therefore, it is necessary to employ a comparability ratio when comparing cause of death statistics across revisions. Comparability ratios have been published by the National Center for Health Statistics (NCHS).

Infant and neonatal mortality rates published in this report are based on all live births regardless of birthweight or gestation. No attempt was made to account for the viability of the infant at birth. These rates for a specific year are based on deaths and live births that occurred during that year. While these live births are not the true population at risk, they are an accurate and timely estimate of that population.

When tabulating deaths by place of death, Other institution is defined as state institution, Veterans Administration facility, hospice, federal institution, health related facility or home for the aged.

Spontaneous Fetal Deaths/Induced Abortions

Fetal deaths include both induced abortions and spontaneous fetal deaths which are presented separately in this report.

Fetal death is defined by New York State Public Health Law ( § 4160) to be the death prior to the complete expulsion or extraction from its mother of a product of conception; the death is indicated by the fact that after such separation, 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.

In 1992, the New York City Department of Health implemented a program to improve reporting of spontaneous fetal deaths. As a result, during 1992, a substantial number of spontaneous fetal deaths recorded in New York City in the years 1991 and 1992 were reported. The data presented here reflect this increase in reporting of 1991 and 1992 events. All tables in this report containing information on 1991 spontaneous fetal deaths have been updated from previously published figures.

Categories used to report operative procedure for induced abortions include dilation and curettage (D&C), suction and curettage, dilation and evacuation (D&E),saline injection, prostaglandin injection, medical (non-surgical) and other which includes hysterectomy, hysterotomy and other procedures. Beginning in 1998, New York City combines saline and prostaglandin injection and this combination is reported in the saline injection procedure.

New York State Public Health Law requires the registration of all fetal deaths regardless of the gestation of the fetus. Unlike birth and death registration, the registration of fetal mortality is not uniform across the United States. In order to provide data comparable to other states, this report presents data for both spontaneous fetal deaths of gestation 20 weeks or more and for spontaneous fetal deaths of all gestations. Due to suspected underreporting of spontaneous fetal deaths, particularly those under 20 weeks gestation, caution should be used when analyzing spontaneous fetal death data.

Population

Population Estimates - The July 1, 1999, estimates were calculated by adding the estimated natural increase during 1990-1999 and the estimated net-migration during 1990-1999 to the 1990 Census population. The estimated net-migration for each minor civil division in the state was based on the average annual net-migration experience during the 1986-1990 period.

The population for New York State exclusive of New York City is the sum of the estimates for the 57 counties in the state outside New York City. The population for New York City is the sum of the population estimates for the five counties of the city.

Population Estimates by Race and Ethnicity - The July 1, 1999, population estimates by race (White, Black and Other) were computed by adding the estimated natural increase during 1990-1999 and the estimated net-migration during 1990-1999 to the 1990 Census Modified Count Population. The estimated net-migration by race for each county in the state was based on the average annual net-migration experience during the 1986-1990 period. After the estimates for the three racial groups were computed, they were adjusted to match the previously prepared estimates of the total population in each county.

The estimates for the Hispanic population was prepared separately using the same methodology as the race estimates. Hispanic population may include persons of any race.

Population Estimates by Age and Sex - The population estimates by age and sex for July 1, 1999, appearing in Table 1 were estimated in two steps. The estimated number of children under five was developed from birth and death data and corrected for estimated net-migration. This migration was based on New York State birth and death data and the 1990 Modified Count data by age and sex. The population over five was estimated using the 1990 population by age and sex, resident death data by age and sex, and estimated migration data by age and sex based on the 1980 and 1990 census. The populations in each age group over five were then uniformly adjusted so that the sum of all the age groups in Table 1 equaled the population estimates for July 1, 1999, for New York City and New York State exclusive of New York City as given in Table 2. The New York State population estimates by age and sex are the sum of the New York City and New York State exclusive of New York City estimates.

The standard five-year age distribution for July 1, 1999, as calculated above was subdivided into single year age groups by using the Sprague multipliers. The single year distributions were then combined to form population estimates for 15-17 and 18-19 age groups for New York City, New York State exclusive of New York City and New York State.

Life Tables: A set of three life tables (Tables 3a, 3b, 3c) is presented which includes the total, male and female populations of New York State. Each life table consists of seven columns.

They are:

Age -- the interval between two exact ages, x to x+n. For example, the age group 15-19 includes the five-year interval of all persons aged 15 to 1 day less than 20 years old.

q-- is the probability of dying during x to x+n. This is the proportion of deaths that occurs during the interval x to x+n among a cohort who were alive at the beginning of the interval.

l -- is the number of survivors at exact age x. Starting with a cohort of 100,000 live births, l is the number of persons who survived to the beginning of each age interval. The number of survivors at the beginning of an age interval multiplied by the probability of surviving the interval gives the number of survivors at the beginning of the next age interval.

d -- is the number of persons dying during x to x+n. This column represents the number of persons from the cohort of 100,000 who die during x to x+n.

L -- is the number of person-years lived during x to x+n. The number of person-years includes those who live the full n years of the interval and those who live less than n years.

T -- is the number of person-years lived beyond exact age x.

E -- is the expectation of life at exact age x. This is the average years of life remaining to be lived by persons of exact age x.

Vital Statistics Rates and Ratios

The definition of the rates used for this report are given below. In a definition, the numerator reflects the number of vital events counted in a specified period of time, usually a calendar year. When the denominator is a population count, it refers to the count at a specified point in time, usually mid-calendar year.

• Live Birth Rate: Annual number of live births per 1,000 population.
• General Fertility Rate: Annual number of live births per 1,000 female population aged 15-44.
• Teenage Live Birth Rate: Annual number of live births to women aged 15-19 per 1,000 female population aged 15-19.
• Spontaneous Fetal Mortality Rate: Annual number of spontaneous fetal deaths (all gestations) per 1,000 spontaneous fetal deaths (all gestations) plus live births occurring during the year.
• Abortion Ratio: Annual number of induced abortions per 1,000 live births occurring during the year.
• Total Pregnancy Rate: Annual number of pregnancies per 1,000 female population aged 15-44.
• Teenage Pregnancy Rate: Annual number of teenage pregnancies per 1,000 female population aged 15-19.
• (Crude) Death Rate: Annual number of deaths per 1,000 population.
• Infant Mortality Rate: Annual number of deaths under one year of age per 1,000 live births occurring during the year.
• Neonatal Mortality Rate: Annual number of deaths under 28 days of age per 1,000 live births occurring during the year.
• Postneonatal Mortality Rate: Annual number of deaths at age 28 days and older but less than one year per 1,000 live births occurring during the year.
• Perinatal Mortality Rate: Annual number of neonatal deaths plus spontaneous fetal deaths of gestation 20 weeks or more per 1,000 spontaneous fetal deaths of gestation 20 weeks or more plus live births occurring during the year.
• Age-Specific Rate: Annual number of deaths in a specified age group per 1,000 population in the same age group. Age is decedent's age at last birthday.
• Cause-Specific Death Rate: Annual number of deaths from a specified cause or group of causes per 100,000 population. Exception: the death rate from complications of pregnancy, childbirth and the puerperium is defined as number of deaths from complications of pregnancy, childbirth and the puerperium occurring during the year per 100,000 live births occurring during that year. This death rate is called the maternal mortality rate. This cause of death category also includes any maternal death which may have resulted from an induced abortion.
• Age-Sex-Adjusted Death Rate (Direct Method): Death rate of a group calculated as a weighted average of the age-sex-specific death rate of the same group. The system of weights is the age-sex-distribution of a population called the standard population. In this report, the standard population is the census count of the New York State modified census population on April 1, 1990.
• Marriage Rate: Annual number of marriages per 1,000 population.
• Dissolution of Marriage Rate: Annual number of dissolutions of marriage per 1,000 population.

Small Area Data

In tabulating vital events for cities and villages with 15,000 or more population, the problem of small frequencies occurs. Statistics based on a small number of vital events are subject to a large degree of variability and inferences should be made with care.

Maps

The maps presented in this report show the rates associated with selected vital events. Population characteristics determine in part the size of these measurements. For each map, the counties are ranked from the lowest to the highest rate. Counties are then classified into four categories: the lowest 10% of all counties, counties ranging from 10 to 50%, counties ranging from 50 to 90% and the highest 10% of all counties.

General mortality rates are influenced markedly by the age and sex distributions of the population. In general, men have higher death rates than women at all ages and people over the age of 55 die at a higher rate than the young.

In those counties different in rates but similar in population characteristics, identification of causative factors can be obtained only by rigorous epidemiological studies, not by simple correlations of vital statistics.