Microdata of National Center for Health Statistics dataset: based on information abstracted from birth certificates filed in vital statistics offices
The natality data from the National Center for Health Statistics (NCHS) provides demographic and health data for every calendar year. The microdata are based on information abstracted from birth certificates filed in vital statistics offices in each state and District of Columbia. We select a sample of five years before 1993 and five years after 1993 to control for the time fixed effects, 11 years of data in total. The main outcome variable is birth weight. Independent variables include treatment variables such as birth year and county residence. Because the data later than 1993 does not have the city of Madison or the city of Milwaukee, we replace Dane County with Madison and replace Milwaukee County with Milwaukee. We also include control variables such as demographic data for mothers like age, race, and years of education.