On IPUMS website, it says “in the 2006-2011 ACS, persons living in Louisiana PUMAs 01801, 01802, 01905 were all coded as living in Louisiana PUMA 77777. Due to the effects of Hurrican Katrina, the original three PUMAs no longer had sufficient population to be separately identified.”
However, I found 16184 observations with PUMA code 1801, 12344 obervations with PUMA code 1802, 0 observation with PUMA code 1905, and 3179 observations with PUMA code 77777 in 2008 3-yrs ACS.
I don’t understand why PUMA 1801 and 1802 still exist but PUMA 1905 disappears. Should it be that all these three PUMAs are grouped into 77777? Does it mean the observations in 77777 all comes from 01905?
Many thanks for any clarifications!