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Within-person injury/poisoning episode identifier


IRINJNUM is a 2-digit numeric variable.


For all injury/poisoning episodes, IRINJNUM reports which injury/poisoning episode this is on the corresponding person record.

In 1997-1999, injuries and poisonings were asked about separately. IRINJNUM is NOT a unique, within person identifier for injury/poisoning episodes in these years. For example, a single person may have two injury/poisoning episodes that both have an IRINJNUM code of "1" if the person had both one injury and one poisoning episode, because each episode was the first episode for the person in the original NHIS public use files that separate injury and poisoning episodes. For 1997-1999, IRINJNUM must be combined with IRPOISYN to uniquely identify each episode within persons. These duplicate values of IRINJNUM are permitted because they correspond to the original codes in the public use files and allow for easier linking.

In 2000-forward, IRINJNUM may be treated as a unique, within person identifier for injury/poisoning episodes. Please see the Comparability Tab or User note on Injuries and Poisonings for more information.

IRINJNUM is an injury-level variable. IRINJNUM 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.


Prior to 2000, persons were asked about injuries and poisonings separately. To improve comparability across samples, IPUMS NHIS integrated all episode level data as a single record type. Episodes that were originally released by NHIS in the poisoning files for 1997-1999 can be identified using the variable IRPOISYN.

Between 1997 and 1999, NHIS only collected detailed information on four injury episodes and four poisoning episodes. Because of the IHIS reformatting of the pre-2000 records to offer all injury and poisoning episodes as a single record type, persons may technically have as many as eight injury/poisoning episodes in the 1997-1999 samples, although the corresponding values for IRINJNUM would be "1", "2", "3", "4", "1", "2", "3", and "4", where the first four represent the four injury episodes and the second four represent the poisoning episodes. Starting in 2000, a person may list up to ten injury and/or poisoning episodes; a person has a record in the injury and poisoning episode-level file for each unique injury and/or poisoning episode (up to ten) that she/he experienced.


  • 1997-2013; 2014 2015 2016 2017: All injury and poisoning episodes.


  • 1997-2017