Codes and Frequencies
HAYFWOASYRC indicates whether the person had chronic hay fever (without mention of asthma) in the past year. This variable is created with supplemental programming by the IPUMS NHIS staff from the pre-1997 condition records. For general information about IHIS variables (such as HAYFWOASYRC) created from the pre-1997 condition records, see the User Note on Condition Records and Condition Variables.
Defining Hay Fever Records and Identifying Persons with Hay Fever
For all available years, persons who were asked a direct question about hay fever and who have a chronic hay fever condition record are given a "Yes" code for HAYFWOASYRC. Persons who were asked a direct question about hay fever but do not have a chronic hay fever record are given a code of "No." Persons who were not asked a direct question about hay fever, or for whom it is unknown whether they were asked such a question, are given a code of "NIU" (not in universe), regardless of whether they have a chronic hay fever record.
For 1970 and 1978-1981, chronic hay fever records were defined as those condition records with a code of "25" ("Hay fever, without asthma") in the variable DIAGR3 in the original NHIS public use files. This condition code value comes from NCHS's Diagnostic Recode #3: Chronic Diseases and Impairments.
For 1982-1996, chronic hay fever records were defined as those condition records with a code of "603" ("Hay fever/allergic rhinitis without asthma") in the variable C1CONDRC in the original NHIS public use files. This condition code value comes from NCHS's Diagnostic Recode C: Chronic Conditions and Impairments.
For 1970, HAYFWOASYRC should be weighted with PERWEIGHT.
For 1978 to 1996, HAYFWOASYRC should be weighted with CONDWT6.
Related Hay Fever Variables
The nearest equivalent of HAYFWOASYRC for 1997 forward is HAYFEVERYR (Had hay fever, past 12 months). However, researchers should use caution when comparing prevalence estimates derived from these two variables, as the manner of collecting information about hay fever differs greatly between the two. HAYFWOASYRC was created by recoding condition records that were generated in response to several different survey questions about health problems underlying disability, sick days, or contacts with health care practitioners in the past year. HAYFEVERYR, by contrast, is based on a direct question about whether the person ever had the condition hay fever.
As with all of the person-level condition variables created by IHIS from condition records prior to 1997, the universe for HAYFWOASYRC is substantially different for 1978 forward than it is for years prior to 1978. Beginning in 1978, only persons living in 1/6 of households, rather than all persons, were asked a direct question about having hay fever in the past year. This change requires that different weight variables be used depending on which years of data are analyzed. See the "Description" tab for details.
Additionally, there is a change in the way "Yes" responses are coded over time. See the User Note on Condition Records and Condition Variables for details about the composite coding scheme employed by IHIS.
- 1970: All persons.
- 1978-1996: Persons living in 1/6 of households (who received Condition List 6).
- 1970, 1978-1996