Dear all, I am interested in working with NIHS data. My understanding is that the survey is conducted every month, on a different sample of individuals.
I would like to know the exact date in which an interview is conducted. I see that only month and year are available, though in the files. Apparently, in the restricted files too. Would you be able to confirm?
In case it is not available, do you happen to know if, for example, interviews are always conducted in a specific week of the month, similarly to what happens to the CPS files? This would help too. I was not able to find this information, apologies.
Interview date is not available in the public use NHIS data. However, it looks like you could obtain this information from the restricted use NHIS data from the National Centers for Health Statistics (NCHS) of the CDC. You can read more about restricted use NHIS data here and read about using IPUMS NHIS data with restricted use NHIS data from the NCHS here. In the 2014-2018 list of variables available in the restricted use NHIS data, I see multiple variables reporting dates of different NHIS interviews, such as SADATE, SAEND, and SCEND. Note that restricted use NHIS data may only be accessed in a Research Data Center (RDC), and that the application process can be lengthy.