What is the difference between metaread(1120) and metarea(112)? Geographically, which code covers which area?

I’m pulling high school graduates for Boston City and Boston MSA, and was wondering why the pulls would be different for detailed metro areas vs. non-detailed metro areas.


Metarea(112) represents the fully harmonized Boston MSA going back to 1850 and metaread(1120) represents the contemporary geographical boundary for Boston. Since IPUMS-USA aims to harmonize variables across time, and often historical data has much less detail then more contemporary data, nesting less detailed variables within detailed variables allows us to offer users as much information as possible (this FAQ response explains things a little better).

Looking specifically at Boston again, if you look at the Codes Section for METAREA and click the “Detailed Codes” radio button near the top, scrolling down to 1120 (Boston, MA), you will see the codes right below it also start with 112 (1121 = Lawrence-Haverhill, MA/NH, 1122 = Lowell, MA/NH, and 1123 = Salem-Gloucester, MA). This means that if you are using the 1990 5% sample and you use metarea(112) you will be including respondents from 1120, 1121, 1122, and 1123. If you would prefer to just select persons from the contemporary Boston geography, use metaread(1120). However, if you are using a pre-1980 sample metarea(112) and metaread(1120) are exactly the same.

I hope this helps.