Data Years Available:
National linked files of live births and infant deaths were first produced for the 1983 birth cohort. Birth cohort linked file data are available for 1983-1991, and both period linked files and birth cohort linked files are available starting with 1995.
The Linked Birth/Infant Death data set includes all variables on the natality (Birth) file, including racial and ethnic information, birthweight, and maternal smoking, as well as variables on the Mortality file, including cause of death and age at death.
To be included in the U.S. linked file, both the birth and death must have occurred in the 50 states or the District of Columbia.
Starting with data year 1995, more timely linked file data are produced in a period data format preceding the release of the corresponding birth cohort format. The 2006 period linked file contains a numerator file that consists of all infant deaths occur.
Response Rates and Sample Size:
Period linked file data starting with 1995 are not strictly comparable with birth cohort data for 1983-1991. Although birth cohort linked files have methodological advantages, their production incurs substantial delays in data availability because it is necessary to wait until the close of the following data year to include all infant deaths in the birth cohort.