This data biography includes information about who created this data, and how, where, when, and why it was collected. We (the Assessment, Policy Development, and Evaluation Unit at Public Health – Seattle & King County) created it to help you understand where the data we analyze and share comes from and its strengths and limitations. If you have any further questions, we would be happy to provide more information or direct you to relevant resources! You can reach us at data.request@kingcounty.gov. 

Who collects the data?  

Birth certificates are completed by hospitals, birth attendants (the person who delivered the baby), and birth certifiers (the person who attests that the newborn is alive at the specified time, date, and place). Data are often collected from a combination of the birthing parent, their medical records, and healthcare providers, and the exact process varies in different facilities.   

Who owns the data?  

The Washington State Department of Health’s Vital Statistics program owns the data, and Public Health – Seattle & King County has access to it through a data sharing agreement with them. 

How is the data collected?   

Birth data are collected using Certificates of Live Birth from the Washington State Department of Health.  Certificates of Live Birth have been completed by hospitals and birth attendants since 1992. It is also possible to register a delivery that was unattended, i.e., that happened at home and was not assisted by a registered birthing attendant such as a midwife. This is done by filling out the Washington State Birth Filing form, Supporting Affidavit, and providing copies of identity, residence, and Acknowledgement of Parentage documents. 

Who is included and excluded from the data?   

The Washington state Vital Statistics for births includes everyone who was born in Washington State, regardless of where they reside currently, and this data is assumed to be complete or near complete. For those who do not give birth in facilities but give birth at home, a licensed birth attendant such as a midwife is still required in order to report the birth certificate data. It is rare for people to be excluded from birth registration data since registration of birth is needed to interact with many systems such as healthcare, early learning, and education. However, if those who give birth at home do not fill out the above-mentioned forms, they would likely be excluded from the data.  

Where is the data collected?  

Birth data is collected from birth facilities, such as hospitals, birth centers, or clinics, which are required to register births within 10 days of delivery. These data reflect births to Washington State residents, regardless of where the births occurred.   

Why is the data collected?  

The Washington State Vital Statistics (Births) data is collected by the Department of Health and it includes data on pregnancy and births in the state of Washington. The information is the used for calculating fertility patterns, birth rates, and maternal and infant health. 

How often is this data collected?  

Birth data is collected after each delivery, typically no later than 10 days after a baby has been born. 

What else is important to know about this data?  

There have been several changes to the way this data is collected and who collects it. For example, changes have been made in reporting race. Birth certificate data before 1990 only included the first race listed on a birth certificate if there were multiple races listed, which greatly increased the number of births that were coded as “White.” Additionally, race codes were more simplified prior to 1992, which led to underestimation of birth rates for Asian subgroups. The data before and after such changes may not be comparable. Other fields that have undergone several changes over time include the mother and father’s ages, medical and health information, previous pregnancy history, and weight gained during pregnancy, pregnancy weight and delivery weight. 

Where can I learn more about this data?   

Washington State Department of Health Birth Data site 

View our King County birth data here 

About data privacy and security  

The Assessment, Policy Development, and Evaluation Unit takes data security and the privacy of all individuals represented in our data very seriously. Data are stored in a secure environment.  For data sets that are not publicly available, only authorized staff are able to access them. Each data set has privacy guidelines to prevent sharing any information that may be identifiable – for example, not sharing (sometimes called suppressing) numbers when they are very small.