ACS Data Users Group

Is there any way to get totals by OMB metropolitan areas using a microdata file other than identifying all the PUMAs within the metro area and adding data for those PUMAs.

IPUMS USA redistributes ACS microdata with added variables that identify metro areas as well as some other geographic info (counties, cities, metro status, metro population, density). See the list of geographic variables here.

Thanks Jonathan. Since IPUMS USA has the metro totals aggregated from the microdata is there any reason that the Census doesn't make that available? I really like the Census front end for selecting variables etc. in creating data downloads, so I would like to see them add geographies such as CBSAs.

Yes, the policy for geographic information in public use microdata is to identify no sub-state entities other than Public Use Microdata Areas (PUMAs) which are specialized units required to have at least 100,000 residents each, helping to protect the identities of respondents. PUMAs subdivide the entire nation, and they can't be designed in such a way to perfectly correspond with all CBSAs or other sub-state geographies. IPUMS USA identifies CBSAs only when the available PUMA information aligns fairly well with CBSAs (within a 15% population mismatch tolerance). This fortunately includes most large metro areas, but it omits many smaller metros and all micro areas. Similarly, IPUMS USA identifies counties only when they correspond exactly to a set of PUMAs. You can click on any variable name in this list to get more info on how IPUMS USA identifies these entities.

Of course, the Census Bureau could use similar policies to identify CBSAs and other areas _when possible_ given the available PUMA info. But it's also true that a large portion of PUMS data users get their data from IPUMS USA anyway--not only for geographic info but for many other added-value features, most notably samples that go back through history with consistent codes across time--so if IPUMS is providing this geographic info already, there's less motivation & need for the Census Bureau to make the effort to do it as well.

Thanks again Jonathan. One other factor with IPUMS, isn't its use restricted to governmental bodies and nonprofit organizations (and not available to businesses and nonaffiliated researchers)? As you know Census data is available to all.

Terms of use for IPUMS data vary among the IPUMS data projects. I believe only IPUMS International and IPUMS PMA (international microdata projects) have the restriction you describe. IPUMS USA, like most other IPUMS projects, has no such restriction, requiring only that you cite IPUMS USA and do not redistribute the data without permission. It is free, and with agreement to these terms, available to all for commercial use as well as non-commercial.

Got it, thanks Jonathan