Are birthplace variables spatially harmonized?
Although the BPL variable provides similar information for all years, the presence of shifting political boundaries and an increasingly diverse population requires more inclusive classification schemes in more recent years. There is nothing done to the birthplace variable that ensures spatial comparability over time as the birthplace variable reports the self-reported birthplace of the respondent within the sample year. More specific notes about comparability issues can be found on the Comparability Tab.
This is a great question! We will continue our spatial harmonization work in coming years, extending it next to migration variables and finally to birthplace variables. Birthplace will be the most difficult since it covers the longest temporal span of any geography variables. The shifting political boundaries, mentioned in the documentation and by Jeff in the previous reply, are especially pronounced for the BPL variable(s).
Thank you so much Jeff and Lara!
I was really hoping your answer to be yes hahaha. But yes, trying to do it by myself for a couple countries made me aware of the difficulties. Again, thank you for your help!
Ohh one more question.
If the variable is just reporting self-reported birthplace, this could correspond to administrative units either at the time of birth or at the time of the survey right?
Or is some correction in place in case the respondent reports an administrative unit that shifted boundaries (so as to move his birthplace somewhere else) or that doesn’t exist anymore?