The “comparability” tab for OCC says 2003-2010 uses the 2000 Census occupation codes. However, when you select 2003 to 2010 under the “code” tab, it brings you to the 2002 Census occupational codes. I figured out there are truly only trivial differences between the 2002 and 2000 Census occupational classification systems (2000 scheme doesn’t have trailing zeroes but 2002 does). But I thought I would point this out this small typo since it appears IPUMS does actually use the 2002 codes. It’s not a huge deal, but the slight format difference can trip someone up if they are trying to create some sort of occupational crosswalk!