What is IHIS?
The Integrated Health Interview Series (IHIS) is a harmonized set of data and documentation based on material originally included in the public use files of the U.S. National Health Interview Survey (NHIS) and distributed for free over the Internet. IHIS variables are given consistent codes and have been thoroughly documented to facilitate cross-temporal comparisons. The “integration” process is described more fully below.
IHIS is not a collection of compiled statistics; it is composed of microdata. Each record represents a person, with all characteristics of that person numerically coded. These person records are organized into households, making it possible to study the characteristics of people in the context of their families or other co-residents. Because the data refer to individuals and not tables, researchers commonly use a statistical package to analyze the records in the IHIS database. A data extraction system enables users to select only the survey years and variables they require. Researchers may also analyze IHIS data using the online tabulator on the website.