US Census data

What is the basis of the underlying data of this site -- it seems that the bulk of it is relying on US Census data?

However, we ‘organize’ our data into geographic areas called MSA’s (Metropolitan Statistical Areas), a term often associated with the Census Bureau.

A Metropolitan Statistical Area (MSA) is a designation the U.S. government uses to refer to a region that, broadly speaking, consists of a city and its suburbs, plus any surrounding communities that are closely linked to the city because of social and/or economical factors. MSAs were known as Standard Metropolitan Statistical Areas (SMSAs) from 1959 to 1983 and, before that, as Standard Metropolitan Areas (SMAs).

The government uses the ‘MSA’ designation for the purpose of applying uniform and consistent standards to the wealth of data collected, analyzed, and published by its various departments and agencies. Official definitions for what constitutes an MSA are developed, issued, and periodically revised by the federal Office of Management and Budget (OMB)

Minimum standards for an MSA are that it contain a population in the urban center of at least 50,000 and a total MSA population of 100,000 or more. 

Because MSA are widely accepted as the ‘standard’ for geographic boundaries, they are used by virtually all data collectors in the private, public, and government sectors.