Is IPUMS data representative at the county level? For example, if I have a PERWT value of 101 for a given county, IND1950 and OCC1950 variable, is it correct to interpret that as being indicative of 101 individuals in that county having that particular occupation and industry? Or is PERWT only apply to the state level?
Which is the lowest level of geography in the ACS PUMS 5 year samples: PUMA or county (when available)?
Is IPUMS ACS data representative at the MSA level?
IPUMS-USA data is representative at both the county level and the state level. As with states, a PERWT value of 101 for a given county, IND1950, and OCC1950 combination can be correctly interpreted as 101 individuals (plus/minus a margin of error) residing in that county having that particular occupation and industry. Keep in mind that the margin of error for a small geographic area will be larger than when based on national data, due to the reduced sample size.
Hope this helps.