yp2uni missing/inapplicable/don't know categories
I am working with the yp2uni variable from the youth questionnaire and I see some incongruence in the missing values.
In Wave 1, there is only the "missing (-9)" category and an "Inapplicable (-8) category. I am not sure what the "Inapplicable" refers to here, as it does not seem like the population to which the question is asked is somehow limited. Moreover, in the questionnaire there is a "I don't know" option, which is not shown in the final data. Might this correspond to the "Inapplicable"?
In Waves 2-5, 7, 10 and 11, there is no "Inapplicable" anymore and just a "Missing" category. Have the two been merged together?
In waves 6,8 and 9, there are categories for both "Inapplicable", "Missing" and "Don't know". This seems like the most comprehensive and correct coding of the data, although it is still unclear what "Inapplicable" refers to in this case.
This issue is quite important for my reserach because an "I don't know" is clearly very different from a missing or an inapplicable response. Moreover, understanding who the "Inapplicable" respondents are is useful to understand which population I am studying here.
Thank you for your help!