Integrated Health Interview Series: Facilitating the use and analysis of NHIS data from 1969-2005

The National Health Interview Survey (NHIS) is an important source of information on the health of the U.S. population, including health status, health behaviors, acute and chronic conditions, healthcare access and utilization, and health insurance coverage. Fielded annually since 1957, it is the longest running national health survey in the U.S. Nevertheless, because of the complexities of file structures, record linkages, and sampling weights, as well as changes in variables, the extraordinary potential of NHIS data for analyses of changing health status, behaviors, and healthcare use has rarely been realized. We report on the Integrated Health Interview Series (IHIS), a harmonized set of data and documentation based on the NHIS public use files from 1969 to the present. This integrated data series will facilitate both cross-sectional analyses and cross-time comparisons of these invaluable health survey data using composite coding schemes to recode variables across time. We illustrate the potential power of the IHIS using a cross-sectional analysis of several complex variables.