Jane F. Gentleman

A preliminary microdata file of January–September data from the 2011 National Health Interview Survey (NHIS) is available through the National Center for Health Statistics (NCHS) Research Data Center (RDC). NHIS data users can analyze these data without having to wait for the annual final NHIS microdata release (at about the end of June).

The NHIS is the principal source of information about the health of the U.S. civilian noninstitutionalized population and one of the major data-collection programs of NCHS. Among the many NHIS microdata and analytic products produced by NCHS are quarterly preliminary microdata files produced by the NHIS Early Release Program and containing selected NHIS variables for use in the RDC. For each data-collection year (January–December), these files are made available three times: in about September (with data from the first quarter), in about December (with data from the first two quarters), and in about March of the next year (with data from the first three quarters). Analysts wishing to use the files should follow standard procedures for using the RDC. Note that NCHS has RDCs in Hyattsville, Maryland, and Atlanta, Georgia. NCHS RDC data also can be accessed remotely and at U.S. Census Bureau RDCs.

Thus, every year, NHIS analysts can use the NCHS RDC to access selected preliminary data as early as nine months before the annual public use microdata release.

The January–September 2011 NHIS preliminary microdata file contains Family Core data for 77,635 persons of all ages, Sample Child Core data for 9,815 children, and Sample Adult Core data for 25,272 adults.