Query of ACS2015 for puma 301-305 (Fairfax County VA) for age(04-18) and schltype, returns twice as many students as are actually enrolled. Something is amiss - syntax? puma? Thanks for all help.
It sounds like you are using the online data analysis tool and entering in a filter of puma(301-305). PUMA values are actually 5-digit values that are state dependent. In other words, they are also associated with a state variable. As such, by using puma(301-305), you are actually looking at data from the following states: AL, CT, HI, MD, MA, NJ, and SC, which may be why you are getting values higher than you would expect. If you are interested in 2015 ACS data, I would suggest reviewing the following resources: 2010 PUMA Definitions and 0010 CONSPUMA Definitions. The information and files contained within these pages should be able to help you identify the appropriate codes for Fairfax County. If you have access to some statistical software (Stata, SPSS, R, etc.) I might also suggest creating an IPUMS USA account and using our data extract system to conduct you analysis.
Here are the source maps for the 2010 PUMAs: https://www.census.gov/geo/maps-data/… specifically for Virginia, and then it looks like all of Fairfax County is at the bottom - there are several of them. You can click on the links to look at the maps to make sure you have full coverage of the county.