Missing Data in Higher Education Codes
I applied for special access to the data 8578 Higher Education Codes. I have now been given the data but I am extremely worried about the number of missing values in the data. Specifically, there are extremely many missing values in the higher education institution for individuals who have a UK higher education degree and who finished in or after 1995. Therefore, I wanted to ask whether this is normal and how come there are so many missing values. Is there any systematic reason of why some individuals were asked the questions regarding their HE institutions and others were not? Or is it simply that some individuals refused to respond - however, I thought that this should be coded as inapplicable rather than missing.
I attach a screen shot of a count of individuals who have a degree but no HE institution information in wave k in comparison to individuals who have a degree but have HE institution information in wave k.
Thank you very much for your help!