Data Cart

Your data extract

0 variables
0 samples
View Cart
Cause of injury or poisoning

Codes and Frequencies

Can't find the category you are looking for? Try the Detailed codes


For all injury/poisoning episodes that occurred in the past 3 months, IRCAUSE reports the interpreted cause of the injury. For each unique episode, the interviewer selected the category for IRCAUSE based on what she/he felt best described the respondent's description of how the injury or poisoning happened. Please see the Comparability Tab for information on how poisonings are assigned in 1997-1999 and 2004-2016 and for information on changes to the response categories available over time. Beginning in 2017, persons could report two causes of injury; this information is available in the variables IRCAUS1 and IRCAUS2.

The related variable IRECAUSNEW recodes the cause of injury using categories based on the ICD-9-CM external cause codes is available through 2014. 2015-2016 data use ICD-10_CM codes, but have not been released. 2017 NCHS documentation notes that ICD-10-CM codes are not included on the public use file. For 2004-2014, IRCAUSE gives more detail about transportation-related injury causes than the related variable IRECAUSNEW, which is based on external cause codes found in IRECODE1, IRECODE2, and IRECODE3.

IRCAUSE is an injury-level variable.

IRCAUSE is part of a series of variables initiated in 1997 that systematically report persons' injuries and poisonings, the cause, what the person was doing while sustaining the injury or poisoning, and where she/he was at the time of the injury or poisoning. For related variables and additional information, please see the User Note on Injuries and Poisonings or use the IPUMS NHIS search function and drop-down menus.


Prior to 2000, poisoning and injury episode-level data were offered by the NHIS in two separate files. For 1997-1999, "poisoning" was not included as a response category because IRCAUSE was only asked for injury episodes. To improve comparability across samples, IHIS integrated all episode level data as a single record type. Episodes that were originally available in the poisoning file have been given a value of "10-Poisoning" for IRCAUSE. This offers more complete information on all episode-level data; however, the assignment of these episodes to the "poisoning" category was done by IPUMS staff based on original data source, not by the interviewer as with other categories for IRCAUSE.. Episodes that were originally released by the National Center for Health Statistics in the poisoning files for 1997-1999 can be identified using the variable IRPOISYN.

Similarly, beginning in 2004, this question was only asked about injuries and not poisoning episodes; to improve comparability over time, IPUMS reclassifies these "out of universe" poisoning episodes to be in universe and have the cause of "Poisoning". As with the 1997-1999 files, this offers more complete information but is not assigned by the interviewer in the same way other IRCAUSE responses are assigned.

The response categories available for IRCAUSE changed over time. Between 1997 and 1999, causes could include transportation, burns/scalds, falls, guns, near drowning, or other. From 2000 to 2003, the gun and near drowning categories were removed and categories such as poisoning, overexertion, animal bites, cuts, machinery, and being struck by an object were added. During this time, the categories were the same for IRCAUSE and IRECAUSNEW. All cases coded as "poisoning" in these years were done by the interviewer as outlined under the Description Tab and are from the original NHIS data. For 2004-2016, IRCAUSE gives more detail about the transportation-related cause of the injury and all other categories were eliminated except burns/scalds, falls, and other causes.


  • 1997-2013; 2014 2015 2016: All injuries and poisioning episodes.


  • 1997-2016