Above, is a scatterplot I made comparing the July 2009 Census Bureau estimated populations of cities with at least 100,000 people (according to the Jul 2009 estimates).
You can look at the spreadsheet I used/created for this here
Missing are the cities with over 1,000,000 people (because they make the rest of the scatterplot too small) as well as those cities with between 100,000 and 1,000,000 people from states the Census Bureau still has to release ( Maine, Massachusetts,Michigan,New Hampshire, New York, Rhode Island, South Carolina and West Virginia).
Notice how the data fits very well(even though the populations in July 2009 were slightly different from those in April 2010), with one glaring exception-the city of Atlanta, where, as it so happens, I now reside.
The July 2009 Estimate put Atlanta's population at 540,922. Today's Census 2010 release of Georgia put the April 1, 2010 population of Atlanta at 420,003, just barely up from the April 1, 2000 Census population of 416,474.
Putting aside that it just seems like there MUST have more than a 3,500 person gain based on residential development in Atlanta in the last 10 years, the chances of a city (in this case Atlanta) being more than 6 standard deviations away from the mean (no other city was more than 2.67 standard deviations away from the mean) is 1 in 500 million (assuming the error here is normally distributed, which it looks to be).
That is to say, it seems MUCH more likely that there's either a typo or a serious undercount of Atlanta's population (I tend to think they undercounted in a lot of places and not just Atlanta personally ...)
This is a very serious issue; the difference in population here is enough to account for about 1/6th of a seat in Congress, 2/3 of a seat in the Georgia Senate, and 2.25 seats in the Georgia House of Representatives, not to mention millions in population-based federal block grants.
I would strongly urge Mayor Kasim Reed to sue the Census Bureau over an undercount of Atlanta.
Anyway, all of that being said, there is the possibility that they somehow majorly majorly overlooked the "black flight" phenomenon, as the official 2010 Census numbers show a 17% increase in the white population of Atlanta but a 12% decrease in the black population (a whopping 65% increase in the Asian population, which is probably due largely to expansion of Georgia Tech). More on black flight later.
