The Bruce Randolph school, Alter explained, “should not be compared to other Colorado schools in affluent neighborhoods”; to consider Randolph’s scores alongside those of white, middle-class schools was like “comparing apples and oranges.” Instead, he argued, the school should be judged on the “stunning” fact that its ninth-grade writing-proficiency rates had doubled since 2007, improving to 15 percent of the class from 7 percent, and that its ninth-grade math-proficiency rates had risen to 14 percent of the class from 5 percent.

A week later, the founder of Urban Prep, Tim King, took to The Huffington Post to defend his school against Ravitch’s charges. King acknowledged that just 17 percent of his 11th-grade students passed the statewide achievement test last year, while in the Chicago public schools as a whole, the comparable figure was 29 percent. But echoing Alter’s fruit metaphor, he wrote that Ravitch was comparing “apples to grapefruits” by holding the students at Urban Prep, who are almost all black males from low-income families, to the standards of “children from all across Chicago.”

To point out the obvious: These are excuses. In fact, they are the very same excuses for failure that the education-reform movement was founded to oppose. (If early reformers believed in anything, it was that every student is an apple.) And not only are they excuses; they aren’t even particularly persuasive ones. By any reasonable measure, students at Bruce Randolph are doing very badly. The average ACT score at Randolph last year was 14, the second-lowest average of any high school in Denver, placing students in the bottom 10 percent of ACT test-takers nationwide. In the middle school, composite scores on state tests put students at the first percentile in reading and writing (meaning that at 99 percent of Colorado schools, students are scoring better), and at the fifth percentile in math. As for Urban Prep: demographic data show that the school’s students are not, in fact, disadvantaged grapefruits among well-to-do apples when compared with the city’s student population as a whole; 84 percent of its students are low-income and 99.8 percent are nonwhite, while in Chicago public schools, 86 percent of students are low-income and 91 percent are nonwhite.

We can quibble about fruit all day, but a more productive response would be to recommit to the principle that 15 (or 17) percent proficiency just isn’t good enough, no matter where you live. To acknowledge this fact is not to say that reform is doomed; it is not blaming students or insulting teachers. It is merely reminding ourselves that the 83 percent of 11th-grade students at Urban Prep who didn’t pass the state exam, and the 85 percent of 9th-grade students at Bruce Randolph who didn’t pass the state writing test, deserve better.

So why are some reformers resorting to excuses­? Most likely for the same reason that urban educators from an earlier generation made excuses: successfully educating large numbers of low-income kids is very, very hard. But it is not impossible, as reformers have repeatedly demonstrated on a small scale. To achieve systemwide success, though, we need a shift in strategy.