Years of Data Used
National Center for Health Statistics - Natality files
Data on deaths and births were provided by NCHS and drawn from the National Vital Statistics System (NVSS). These data are submitted to the NVSS by the vital registration systems operated in the jurisdictions legally responsible for registering vital events (i.e., births, deaths, marriages, divorces, and fetal deaths). We requested this data for the first time for the 2018 Rankings. This was done because of the discontinuation of Health Indicators Warehouse. This change also allows to to perform additional analyses for state and national reports which if obtained from CDC WONDER would have numerous missing counties.
Counties can find the same data from CDC WONDER. However, we use the raw data files. CDC WONDER does not report data for all counties per their missing data criteria.
The methods for calculating the error associated with death rates can be found here:
For counties with fewer than 20 births a missing value for all values is reported.
For counties with between 20 and 99 births a gamma adjustment from the poisson distribution is used to calculate the CIs (see page 87: http://www.nber.org/mortality/2002/docs/techap99.pdf).
For counties with 100 births or more CIs are calulated according to the normal distribution. Standard errors (SE) and birth rates for each age group are calculated. These SEs are squared and multiplied by the square of the weights and then divided by the total number of births over all age groups. The sum of these provides the variance of the estimate for each county. The square root of the variance gives the standard deviation which is then used as estimate +/- 1.96*STDEV.
County-level data are available for counties with populations of 100,000 persons or more in CDC WONDER, and you can stratify by the age, race, or education of the mother among other variables.
Another way to access this data is through the Community Commons Health Equity Assessment Report. Data by race can be found for some communities. Note that you will need to login to access this report, but registration is free for all.