Understanding Society User Support

Dear Understanding Society team,

I am interested in using Understanding Society data for my PhD project and I am writing you regarding the variable measuring father’s and mother’s educational qualifications. It is not clear to me why there is such a high number of -8 (‘not applicable’) cases. After matching the two waves (a&b) there is still a high number of ‘not applicable’ cases. Most probably this is connected with ‘universe’ specified in each questionnaire, i.e.:

Wave A:
Universe
if [month = 1,2,3,4,5,6] Sample month is January 2009 to June 2009

Wave B:
Universe
if [ff_sampst = OSM & ff_monthly in (JY1..DE2)] original sample member to be interviewed after 8-July 2010 i.e.July year 1 to December year 2

I would really appreciate if you could clarify for me what is the reason behind the ‘not applicable’ cases.
Could you please confirm if the data collection for this variables ended at the end of year 2 wave 2, namely December 2011? And also when the ‘year 2, wave 2’ data is going to be released?

Thank you very much,
Adriana