Over-assessment is a neighborhood problem.

Line up Fulton County's cities by over-assessment rate and the county stops looking like one place. One housekeeping note first: the rates below are computed on the 190,178 homes where the sales evidence lets us state a value with confidence — 31,216 of them are over-assessed, which is 16.4% of valued homes and the “1 in 10” of everything we examined.

At the top, East Point: 31.2% of the homes we can value are over-assessed — 2,702 homes in a city of under 40,000 people. At the bottom, Roswell: 7.3%, or 1,401 homes. A homeowner in East Point is more than four times as likely to be over-assessed as one in Roswell — under the same tax authority, valued by the same office, in the same year.

The middle of the table matters too. Atlanta sits almost exactly at the county rate — 16.1% — which is what you'd expect from a city large and varied enough to be most of the county average. Milton and College Park land at nearly the same rate despite being, by most other measures, very different places. The gradient isn't a north-south morality tale; it's a map of where the county's valuation model has good evidence to work with and where it doesn't.

Cities are still averages, and averages still hide things. East Point's 31.2% is not spread evenly across East Point, any more than the county's 16.4% is spread evenly across the county.

The honest unit of analysis is the neighborhood. Across the hundreds of Fulton neighborhoods large enough to measure, the over-assessment rate spans from 0% to 93%. There are neighborhoods where we found essentially no over-assessment at all, and neighborhoods where nine homes in ten are taxed above what the sales evidence supports. No other way of cutting this data — by home value, by home condition, by anything — produces a spread anywhere near that wide. Geography dominates.

Why? The short version of the first article in this series: the county has to value every home, so it uses a model calibrated to be right on average across the whole market. That works well where sales are dense and homes are alike — the model has plenty of nearby evidence to lean on. It works worst where sales are sparse, homes are older and more varied, and the model has to reach further afield for comparisons. The neighborhoods at the top of the over-assessment range are, overwhelmingly, the second kind of place. The concentration isn't a decision anyone made. It's what “right on average” looks like from the places the average fits worst.

The rate table tells you where over-assessment is most likely. It does not tell you where most over-assessed homeowners live — and the answer is different, and worth being honest about.

Atlanta, at a rate barely above the county average, contains 11,906 over-assessed homes — about 38% of all the over-assessment in Fulton County, more than the next four cities combined. South Fulton holds 6,488 (about 21%), East Point 2,702 (about 9%). The highest-rate places and the highest-count places overlap, but they are not the same list, and any serious account of this problem has to carry both numbers at once: East Point has the county's worst odds; Atlanta has the most affected homeowners.

What is all of it worth? Across the 31,216 over-assessed homes, we estimate roughly $49 million a year in property taxes above what the sales evidence supports — a typical (median) overcharge of $804 per home per year, with a mean of $1,577. These are estimates, built from publicly available sales data and subject to verification home by home; individual results vary, and some of these homes, on closer inspection, will turn out to be fairly valued. But the shape of the finding doesn't depend on any single home being right. Over-assessment in Fulton County is real, it is large, and it is anything but evenly distributed.