NHISIID is an 19-character string variable.
Description
NHISIID is an IPUMS NHIS-constructed value that is an identifying number unique to each injury or poisoning record in a given survey year. Using NHISIID, analysts can link IPUMS NHIS data with additional data elements, from the NHIS source public use data files, that are not currently available in IHIS. For example, researchers can use NHISIID to link variables in IPUMS NHIS with other variables from the core NHIS files variables. Alternatively, users may use NHISIID to link variables from IPUMS with variables from NHIS supplements that are not yet part of IPUMS NHIS. NHISIID is a single variable constructed by concatenating multiple data elements from the NHIS source data files.
Analysts wishing to link household-level NHIS data should use the household-level linking key NHISHID.
Analysts wishing to link person-level NHIS data should use the household-level linking key NHISPID.
See the user note on LINKING for instructions on how to create links between IPUMS NHIS and NHIS source data.
Comparability
The variables concatenated to construct NHISIID differ by periods. There are three discrete periods, namely: 1) 1997-1999, 2) 2000-2003, and 3) 2004-forward. While the particular combination of variables used to construct NHISIID differs between these periods, the substantive meaning of the variable is consistent across years. In the discussion that follows, the elements of NHISIID are identified via the variable names used in the original NHIS public use data source files.
From 1997 through 1999, the sequential elements of NHISIID are processing year (YEAR), household serial number (HHX), family serial number (FMX), person number (PX), an IHIS-generated flag variable that indicates if the record was originally from the injury or the poisoning file (IRPOISYN), and the within-person injury number (INJEPNO/POIEPNO in the NHIS data or IRINJNUM in the IPUMS NHIS data).
Beginning in 2000, when the injury and poisoning records were collected as part of a single file, and until 2003, the sequential elements of NHISIID are processing year (YEAR), household serial number (HHX), family serial number (FMX), person number (PX), and the within-person injury/poisoning number (IPEPNO).
For 2004 forward, the sequential elements of NHISIID are processing year (YEAR), household serial number (HHX), family serial number (FMX), person number (FPX) and the within-person injury/poisoning number (IPEPNO).
Universe
- 1997-2013; 2014 2015 2016 2017: All injury and poisoning records
Availability
- 1997-2017
Weights
- 1997-2017 : PERWEIGHT
