Geographic unit Ethiopia 2007 census

I want to use the 2007 Ethiopia census for analysis. I wonder, however, at which admin level the census provides representative information. The sample overview information states that the geographical unit is the Zone, which is admin level 2. However, when I look at various census documents and at a description of the census at the World Bank microdata website (Ethiopia - Population and Housing Census 2007 - IPUMS Subset), the refer to the wereda, which is a admin level 3. I suspect that it is the latter, which means there is a mistake on the IPUMS website. Can you please clarify?

Thanks,
Michiel

Wereda (Admin Level 3) is available in IPUMS for the Ethiopia 2007 sample and provides representative information. It likely was not listed on the sample characteristics page because IPUMS International does not spatially harmonize Level 3 geography. If you use Wereda for your analysis, keep in mind that it is harmonized by name and does not take into consideration changes in boundaries over time.