Birth Data Release Notes

General Release Notes

2022 Birth

Population Estimates

HHDW has two population rates available. The Population Rates module should be used to examine births by sex, age, and geography (state and county) and has annually updated Census data as the denominator. The Population Rates by DOH race/ethnicity (only) module allows users to examine births by Hawaiʻi specific race/ethnicity and is based on a 5-year aggregate population that is held constant across years. The population estimates for both modules come from the U.S. Census. The population data in the Population Rates module come from the American Community Survey 1-year estimates. The population data in the DOH race/ethnicity (only) module are based on a special 5-year aggregate created for HHDW by the Census to approximate the race/ethnicity algorithm used by the Hawaiʻi State Department of Health's Office of Health Status Monitoring to assign a single race/ethnicity to each person (see here).

With the 2022 birth record data, new Census data was uploaded for 2020, 2021 and 2022, and a new DOH race/ethnicity data file was loaded for 2016-2020. The HHDW team compared the race/ethnicity population estimates from the 1-year and 5-year aggregates and determined that the Census race population estimates are not comparable to the way race/ethnicity is coded on the birth certificate. Therefore this option has been temporarily removed from the Population Rates module. These updates to the population reference files may result in population rate changes from 2020 and 2021 and race/ethnicity rate changes from 2016 forward.

Race/Ethnicity Data

HHDW has been working on standardizing the category descriptions across data sets. As part of this standardization the display order for DOH Race/Ethnicity has been changed to be the same across all data sets. The new display order is:

American Indian or Alaska Native
Black
Chinese
Filipino
Japanese
Other Asian
Native Hawaiian
Other Pacific Islander
White
Other

The display order for Census Race has also been changed to be the same across all data sets. The new display order is:

American Indian or Alaska Native
Asian
Black or African American
Native Hawaiian and Other Pacific Islander
White
Other

2021 Birth

Race/Ethnicity Data

HHDW has been working on standardizing the category descriptions across data sets. As part of this standardization the category for "White" has been made the standard category title, replacing "Caucasian" in some data sets. Also, a standard description of "American Indian or Alaska Native" has been set to replace a variety of category names. See the table below for the updated mapping of Program Race/Ethnicity, DOH Race/Ethnicity and Census Race.

2019 Birth

New Primary Care Service Area Dimension

We have added a new geographic dimension to the Birth Module to cover primary care service areas. Primary care service areas were created to describe the delivery of primary health services in the State of Hawaiʻi through participation of multiple stakeholders in the early 1990's. The rural health associations of the Hawaiʻi, Maui and Kauaʻi Counties delineated rational service areas under their respective jurisdictions. Neighborhoods were clustered into primary care service areas to provide information below the county or island level with demarcation between adjacent neighborhoods. Census tracts were used in defining these areas due to their availability in census and vital statistic data.

Here is a link to a document containing the Census Tract to Primary Care Service Area Crosswalk:

HHDW Census Tract to Primary Care Service Area Crosswalk

2018 Birth

New Cell Suppression Criteria

Cell suppression criteria have changed. In accordance with data use restrictions set forth by Hawaiʻi State Department of Health (DOH) and the National Center for Health Statistics (NCHS), cell counts of fewer than 9 events and rates based on counts of 9 or fewer will be suppressed, and rates based on counts of less than 20 will be regarded as unreliable and will also be suppressed. Suppressed data is denoted with a double asterisk (**).

2014 Birth

Changes to the Birth Certificate

A new birth certificate data collection form was implemented in Hawaiʻi in 2014. This new form and some procedural changes in how some data elements are captured resulted in discernable differences in some of these data elements before and after the change. In prior years, infant gestational age at birth was calculated based on the date of last menstrual period as reported by the mother. As of 2014, gestational age is based on the health care provider's assessment; therefore, dimensions based on gestational age cannot be trended. Accordingly, HHDW has created three new dimensions starting in 2014:

Infant's Gestational Age (2014+)
Mother's Education Level (2014+)
Trimester Prenatal Care Began (2014+)

Birth method data (Birth Type) has also been impacted by this data collection change. We are working with the Office of Health Status Monitoring at DOH to determine the best way to handle these changes. In the meantime, analysis by birth method is limited to 2000-2013.

All Years

Population Estimates for Population-based Rates

Annual population estimates are extracted each year from the U.S. Census, Population Division, Annual County Resident Population Estimates. These estimates change each year and provide the denominator for the crude birth rates, fertility rates and teen birth rates, by age, sex and census race, for the years 2000-2022.

However, population estimates for Hawaiʻi-specific race/ethnicities (DOH Race/Ethnicity) are not reportable for individual years, so special 5 year aggregate population estimate files were created for Hawaiʻi, by the Data Products Development Branch, American Community Survey Office, U.S. Census Bureau. These 5 year aggregate (2010-2014 and 2016-2020) files were used to create two average annual population estimates: the 2010-2014 file was used to create the population estimates for the years 2010-2015 and the 2016-2020 file was used to create the population estimates for the years 2016-2022. These estimates are used for all population-based rates by DOH Race/Ethnicity for the years 2010 forward.

Because HHDW uses two different population estimate files, birth rates may vary slightly depending on which category you select your birth rate indicator from - Population Rates with Census Race vs Population Rates by DOH Race/Ethnicity ONLY. Census Race and DOH Race/Ethnicity rates should not be compared directly.

Residence

Data can be analyzed geographically by mother's residence or infant's place of birth. Mother's residence is based on the address provided on the birth certificate as the place where the mother resided at the time of the birth. Military members and dependents who live in Hawaiʻi at the time are classified as residents. Visitors who give birth while in Hawaiʻi but do not reside in Hawaiʻi will not appear in queries by Mother's residence.

There are two measures for capturing geography in the Birth Record - zip code and census tract. Island, school complex and community are based on zip code and county and primary care service area are based on census tract.

Infant's birth location includes all live born infants in Hawaiʻi regardless of the mother's place of residence. Infant's birth location will not always correspond to the mother's place of residence; for example, an infant can be born in Honolulu to a mother who resides in Kauai.

Race/Ethnicity Data

The birth certificate allows for up to 4 race/ethnicities to be captured for both the mother and the father. The DOH Office of Health Status Monitoring (OHSM) uses the following algorithm to code a single race/ethnicity for each individual. Ethnicity of the child is based on the ethnicity of the father. It is based on the ethnicity of the mother when the ethnicity of the father is unknown.

Only one ethnicity is coded from the actual certificates. If more than one ethnicity is listed on the certificate, the following rules apply:

In HHDW, the most granular level is the program race/ethnicity (PRG) which rolls up into the DOH standard race/ethnicity (DOH), which rolls up into Census race reporting categories (Census). The table below illustrates how the data is aggregated.

Race/Ethnicity Classifications
Source Race/Ethnicity	Program Race/Ethnicity (PRG)	DOH Race/Ethnicity (DOH)	Census Race (Census)
American Indian	American Indian	American Indian or Alaska Native	American Indian or Alaska Native
Asian Indian	Asian Indian	Other Asian	Asian
Black	Black	Black	Black or African American
Chinese	Chinese	Chinese	Asian
Cuban	Cuban	Other	Other
Filipino	Filipino	Filipino	Asian
Guamanian	Guamanian	Other Pacific Islander	Native Hawaiian and Other Pacific Islander
Hawaiian	Hawaiian	Native Hawaiian	Native Hawaiian and Other Pacific Islander
Part Hawaiian	Part Hawaiian	Native Hawaiian	Native Hawaiian and Other Pacific Islander
Japanese	Japanese	Japanese	Asian
Korean	Korean	Other Asian	Asian
Other Asian	Other Asian	Other Asian	Asian
Mexican	Mexican	Other	Other
Portuguese	Portuguese	White	White
Puerto Rican	Puerto Rican	Other	Other
Samoan	Samoan	Other Pacific Islander	Native Hawaiian and Other Pacific Islander
Vietnamese	Vietnamese	Other Asian	Asian
White	White	White	White

Documentation

Documentation is available here to describe how we collect and map race/ethnicity, geography, and poverty level.

HHDW Race/Ethnicity Documentation

HHDW Geography Documentation

HHDW Poverty Level Documentation

Kotelchuck Index Documentation

The Kotelchuck Index, also called the Adequacy of Prenatal Care Utilization (APNCU), uses two crucial elements obtained from birth certificate data-when prenatal care began (initiation) and the number of prenatal visits from when prenatal care began until delivery (received services). The Kotelchuck index classifies the adequacy of initiation as follows:

pregnancy months 1 and 2,
months 3 and 4,
months 5 and 6,
and months 7 to 9

with the underlying assumption that the earlier prenatal care begins the better. To classify the adequacy of received services, the number of prenatal visits is compared to the expected number of visits for the period between when care began and the delivery date. The expected number of visits is based on the American College of Obstetricians and Gynecologists prenatal care standards for uncomplicated pregnancies and is adjusted for the gestational age when care began and for the gestational age at delivery.

A ratio of observed to expected visits is calculated and grouped into four categories:

Inadequate (received less than 50% of expected visits),
Intermediate (50%-79%),
Adequate (80%-109%),
Adequate Plus (110% or more).

The final Kotelchuck index measure combines these two dimensions into a single summary score. The profiles define adequate prenatal care as a score of 80% or greater on the Kotelchuck Index, or the sum of the Adequate and Adequate Plus categories. The Kotelchuck Index does not measure the quality of prenatal care. It also depends on the accuracy of the patient or health care provider's recall of the timing of the first visit and the number of subsequent visits. The Kotelchuck Index uses recommendations for low-risk pregnancies, and may not measure the adequacy of care for high-risk women. The Kotelchuck Index is preferable to other indices because it includes a category for women who receive more than the recommended amount of care (adequate plus, or intensive utilization).

The rate of this number is per 100 live births where prenatal care adequacy using the Kotelchuck Index was known. Additional information on the Kotelchuck Index can be found here: OVERVIEW OF ADEQUACY OF PRENATAL CARE UTILIZATION INDEX