A question about missing value -99

Dear NEPS team,

I have a question about the definition of missing values (coded as -99) in NEPS data.
In the NEPS data manual, it says -99 is a „filtered“ missing value.
What does „filtered“ mean? When were the questions filtered?
It will be great if anyone could give me more information on this. Thank you in advance!

Best regards,
Ai Miyamoto

Dear Ai,
„Missing due to filtering“ means that a person was not asked a question because some prerequisite was not valid. For example, if a person states that they do not have a partner, they will of course not be asked questions about their relationship, but rather will be “filtered out”. However, the value -99 only occurs, for example, in studies in which the survey mode was PAPI or CAWI. In CATI/CAPI mode, the value „. sysmis“ is assigned for filter-related missings.

Kind regards,
Benno Schönberger

Dear Benno,

Thank you very much for your quick reply! That was really helpful.