IHIS: Definition of NIU for "ganxietyev" variable

#1

For the variable “ganxietyev” (Ever had general anxiety disorder), over 68% of the population is “NIU” or not in the universe. The universe tab for ganxietyev states “2008: Sample adults age 18+.”

Would this mean that all those not in the universe are under the age of 18, or does this also include individuals who were not surveyed about general anxiety disorder?

I’m trying to find the prevalence of general anxiety disorder for a population, so would I exclude the NIU answers and therefore scale up the responses for the smaller population?

Thank you for your help!

#2

Notice that the Universe Tab of GANXIETYEV states: “Sample adults…”. The NHIS is structured in a unique way where there are a core group of questions that are asked to everyone in the sample, and several supplemental questionnaires that are asked to a random sample of adults or of children. This question about general anxiety is only asked of the randomly sampled adults. You can track down who was in the adults sample by using the ASTATFLG variable. Once you control for whether or not a record was part of the adult sample, you should be able to calculate a much more realistic share of individuals with anxiety.