I'm working with W1-6 of UKHLS and have noticed that in W6 there are 4656 cases where fimngrs_dv==-9. According to the online documentation these cases have missing incomes.
I'm curious as to why W6 contains missing incomes given that there don't appear to be any fimngrs_dv==-9 cases in the previous waves. Furthermore, all these W6 cases seem to have completed some kind of interview and I can't see any obvious pattern in their employment status. All -9 fimngrs_dv cases have however been imputed so I wonder if that is something to do with it. Any help you can offer would be much appreciated.
Also I think the header of the online documentation of this variable may be incorrect. It doesn't seem to give the right SN code for the Special Licence UKHLS files where income is not top coded.