Data provided on PeriStats may differ from rates obtained by state health departments and vital statistics agencies. This could be due to multiple causes. As part of the Vital Statistics Cooperative Program, states are required to send the National Center for Health Statistics (NCHS) natality and mortality data for a given year by a specific date. Sometimes states receive data after this date, which may result in slight differences in the rates calculated using NCHS-processed data and state processed data. Another reason rates may vary could be due to differences in the way NCHS and the states calculate variables and impute missing data. Please see the Calculations section of the Web site for a more detailed description of the methods used to calculate specific health indicators on PeriStats.

While one strength of PeriStats is the ability to make comparisons between states/local areas or between any state/local area and the U.S., the web site is only a starting point for obtaining state and local data. We encourage users to work with their state health departments to analyze data in order to gain a deeper understanding of maternal and infant health issues specific to their area. Web site links for all state health departments are available on PeriStats.