People are way over-thinking this. Atl's methodology is meant to do one thing, tell applicants which schools are most likely to get them a legitimate law job (especially biglaw) upon graduation.
In many ways, it's addition by subtraction. It eliminates worthless metrics found in other ranking systems; yet its results are mot that different from those of USNWR. I would be far more likely to rely on ATL's ranking than that of USNWR, especially since it gives a bump to many of the so-called T2 schools people have argued for years are really tier-1 caliber. They prove their mettle by pulling the employers, and that's really what counts.
The supposedly "missing" Utahs, Arizonas, Hastingses, Colorados, etc. are probably in the #51-60 range, but who cares? Why are people so stuck on this notion that USNWR has to be right? It has more flaws in it than any system except Brenner's.
ATL reasonably mirrors USNWR because of "stabilization": over time the USNWR rankings created a self-fulfilling prophesy that ultimately caused employers to recruit according to the rankings. The end result is that employment results have pretty much mirrored reputational rankings.
Aberrant schools like New Mexico can be explained by geography. They tend to be the only game, the best game, or one of the best games in their markets, so of course their employment stats belie their rankings. Miami? Houston? New Mexico? It's easy to see how they would crack the ATL top-50 in a purely employment-based ranking driven by the economy. It's also very easy to see how a school like Hastings would suffer: it's located in over-saturated market.
But most reputable law schools have suffered over the last decade -and-a-half as a result of USNWR's questionable methodology. The two rankings would have looked very different in the 1990's. Back then, schools like Temple, Brooklyn, Loyola, Howard, Suffolk, Chicago-Kent, and maybe even Seattle U and Oregon would have been included in ATL's top-50. It's an economy-driven ranking.
Additionally, USNWR is not transparent and includes false data. Which judges are weighing in on reputation rankings? Morse won't release that info. I know many prominent municipal, superior court and federal judges, but I have yet to meet one who has ever received a survey or knows another judge who has received one.
ATL is spot-on! What matters most is that you attend a school that doesn't lie to you...one at which you can find enjoyment, fulfillment and a job that allows you to pay off any debt you incur. I think ATL's ranking is reliable.