To anyone who cares about ensuring that all children are educated to a high standard, it is depressing to look at one of those graphs that show schools by percentage of low-income students on the x axis and academic achievement on the y axis. The steep slope down and to the right seems to demonstrate an iron law of probability: High-income schools have high achievement; low-income schools have low achievement. Even more uncomfortable for a country that often prides itself on having eliminated institutional discrimination, the same results can be replicated when race rather than income is used.

But if you take your eye to the upper-right quadrant of that graph, you'll often see an outlier or two—that is, high-achieving schools with a high percentage of students of poverty or students of color.

What are those schools like? Are they there because of a one-time fluke? Are their poor kids the children of impecunious grad students? Are their students of color the children of doctors or lawyers?

After eight years of studying schools in the upper-right quadrant, we can say that their presence there is rarely a fluke.

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