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Number times in ER/ED in past 12 months

Codes and Frequencies

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For sample children and sample adults, ERYRNO reports the number of times respondents had gone to a hospital emergency room about their own health during the past 12 months, including emergency room visits that resulted in a hospital admission. Respondents were handed a card listing a range of responses and were asked to indicate the appropriate response.

The Field Representative's Manual for 1997 forward cautioned interviewers, "When recording emergency room visits, do not include visits to outpatient clinics and urgent care facilities." The Manual also defined "hospital emergency room" as "an emergency care facility at a hospital. It is also sometimes referred to as an emergency department" and reiterated, "Do not include emergency care received at a clinic or HMO." Emergency room visits that resulted in admission for inpatient care were to be included. The definition of an emergency room and these qualifications were not routinely shared with respondents, however.


Responses for 2000 forward were grouped into smaller intervals than was the case for 1997-1999.


In earlier period, 4 to 9 visits were grouped together; in the later period, intervals of 4 to 5 visits, 6 to 7 visits, and 8 to 9 visits received separate codes. Similarly, in the earlier period, a single code covered 13 or more visits; in the later period, 13 to 15 visits and 16 or more visits received separate codes.

To maximize comparability over time, a composite coding system was used.


The first digit groups together responses according to the coding scheme used for 1997-1999, while the second digit recognizes the additional detail available for 2000 forward. Thus, for example, all values encompassing the range of 4 to 9 visits have a code of 4 for the first digit, while subcategories available for 2000 forward only are distinguished in the second digit (i.e., 4 to 5 visits is coded 41, 6 to 7 visits is coded 42, and 8 to 9 visits is coded 43). For comparability across all years, users should group together responses with a common first digit; to make use of the additional detail available for 2000 forward, users should distinguish between codes differing in the second digit.

Questionnaire design changes introduced in 2019 limit comparability with earlier years. The NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.


  • 1997-2018: Sample adults age 18+ and sample children under age 18.
  • 2019-2022: Sample adults age 18+ and sample children age 0-17.


  • 1997-2022