The release of new census figures last week brought with it a wave of excitement over what seemed to be a migration back to the city. But as Briem points out, the supposed spike, reported extensively in major news sources, appears to be a misreading of the data and methodology.
The Census Bureau altered its methodology for calculating population in subcounty areas (i.e. cities, among other places) this year, and is "likely to change it again before next year's update." More specifically:
"To produce subcounty housing unit estimates, we distributed the extrapolated county estimates down to each subcounty area within a county based on 2010 Census proportions." (emphasis added)
In other words, "the Census basically took the growth... and just assumed it was spread evenly between center cities and suburbs within counties across the nation. The result was that it all of a sudden appeared cities were growing faster (or in some cases shrinking less) than they have been in other data. In reality, the new patterns were no more than an artifact of the temporary change in the Census Bureau's methodology for this data."