Closing the Scarsdale-Harlem gap

New York City charter schools are closing the Scarsdale-Harlem achievement gap, concludes Stanford researcher Caroline Hoxby in a new study.  Low-income, minority students who attended a charter school from kindergarten through eighth grade closed 86 percent of the achievement gap in math and 66 percent in English language arts compared to affluent suburban students in Scarsdale. For each year spent i a charter school, students are more likely to earn a Regents diploma. Some 30,000 New York City students attend charter schools, while 40,000 sit on waiting lists trying to get in. Charter students outperform similar students who lost charter lotteries, the study found.

A 15-state study by the Center for Research on Education Outcomes, also at Stanford, found most charter students do not outperform students in nearby public schools, reports Ed Week’s Debra Viadero. Some speculate that New York City charters are better than charters in other locations.

But another possible explanation for the sharply contrasting results, said Ms. Hoxby, may be that the CREDO findings suffer from a “serious mathematical mistake.” The problem, she said in a separate analysis, is that (Margaret) Raymond compared the achievement of individual charter students with that of groups of students from nearby public schools, without making the statistical adjustments necessary to account for the natural downward biases that result from that sort of calculation.

Hoxby’s research found successful New York City charters have a longer school year.

Likewise, researchers found that the average charter school in the study stayed open eight hours a day, with some providing services for as long as 10 hours.

Other school characteristics associated with better student achievement included: more time spent on English instruction; teacher pay plans that were based on teachers’ effectiveness at improving student achievement, principals’ evaluations, or whether teachers took on additional duties, rather than traditional pay scales; an emphasis on academics in schools’ mission statements; and a classroom policy of punishing or rewarding the smallest of student infractions.

Class size, parent contracts and number of years in operation did not correlate with achievement. , according to the report.

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  1. I am not generally impressed with charter vs traditional comparisons–too many variables on both sides. What does come out of this that has value, to my mind, is the specifics that appear to correlate with achievement, as well as those that do not.

  2. “I am not generally impressed with charter vs traditional comparisons–too many variables on both sides.”

    I agree. The value in charters is that they provide the necessary variation as individual entities. We can see what type of charter works and which ones fail, pariticularly with the low performers or low socio-economic status populations.

    Those successful charters, serving low SES kids, are the gold hidden in the chafe. They give us the information we need to improve both low performing charters and public schools.

  3. Diana Senechal says:

    The Hoxby study does not say how many students actually stayed at a charter school for all of grades K-8 (or for any portion of those years), or what their ratio was to the charter school student body in NYC as a whole. This is important information, since the study states that those who stay in charters in all of grades K-8 close most of the “Scarsdale-Harlem” achievement gap.

  4. It caught my attention that, “an emphasis on academics in schools’ mission statements” correlated positively with achievement but “parent contracts” did not. Since both of these seem like general fluff, I wonder what is going on.

  5. What’s going on is that Hoxby’s piece is nothing more than propaganda for the “reform” crowd. Notice that is is NOT published in any peer reviewed journal, but at the friendly (to her) pages of the website, a pro-charter group.

    Don’t be surprised when researchers poke holes in this study, and someone claims this was a “working paper” never intended for publication. And by publication I mean scrutiny.

  6. Caroline Hoxby, who conducted this so-called “study,” is not an impartial academic researcher. She’s a longtime, high-profile proponent of free-market “solutions” and privatization. Her work should not be treated like credible academic research; it’s advocacy — or propaganda, if you will.

    I’m really shocked that the mainstream press is not even including disclaimers to this effect in its massive hyping of this so-called study. That truly violates media standards and ethics, and misleads the reader.

    Here an analysis of the flawed study itself, by a New York blogger. But to me it’s also a huge issue that the press has simply abandoned its standards and ethics by reporting on this propaganda as if it were credible academic research.

  7. Diana Senechal says:


    You make good points–the media has taken Hoxby’s study as pure “findings” and has failed to scrutinize it more closely. I wrote on Gotham Schools about unanswered questions in the study.

    But I have trouble with the bias argument. Most people in education are biased, from what I can see. Bias on its own does not disqualify someone from conducting a study. We have to look at the study on its own merits and see whether bias has played into it–whether the author has set up the study to point to certain results (or is distorting the results).

    The study does not say how charter students as a whole performed in relation to their lotteried-out counterparts. It does not say how many students (in relation to the whole) stayed in charters for one, two, three, four, or more years. And it does not look at “lotteried-out” students who stayed in the same public school vs. those who switched schools. Is the contrast here between stable and unstable learning environments, or between charter and public schools?

    The findings of the study pertain not to charter school students in general, but to students who have stayed in charters for a number of consecutive years. We need more information about these students and the schools they attend. We need more information about the students with whom they are compared.

  8. “It caught my attention that, “an emphasis on academics in schools’ mission statements” correlated positively with achievement but “parent contracts” did not. Since both of these seem like general fluff, I wonder what is going on.”

    The “parent contracts” caught my eye as well, although I missed the mission statements. My own observation is that either of these can serve as “fluff,” or as useful tools, even though I would agree that I have observed a good deal of fluff. I suspect that even a poorly written and observed mission statement has, at a minimum, some angst attached to it. This is how I account for the number of meandering and qualified mission statements that I have seen. Something like: Our mission is to provide an excellent education to the best of our ability and resources to any student who is willing to extend and apply themselves with the support of their family and community. (OK–I made that one up, it’s a parody). At least this duck and cover approach acknowledges some expectation that a mission statement will guide the work of the organization, help to set goals, and so forth.

    By contrast, while parent contracts are actually meant to provide a tool for laying out an agreement between two of the key parties in a student’s education–fostering communication about expectations on both sides–what I have generally seen is some piece put together by someone far, far away, and waved under a parent’s nose at orientation or open house. It’s always sort of a “you do your job and I’ll do mine” thing with a “by the way, I’ll decide what my job is, and then I’ll tell you what your job is.” Personally, I refuse to sign as a matter of principle. No one has ever even noticed.

    So, perhaps if a mission statement actually focuses on academics, it indicates that someone is making a link between it, and the work at hand.

  9. Yes, everyone has opinions, of course. But Hoxby is previously best known to the public as a vigorous advocate of “free-market solutions” in education, including charter schools. To me and I believe to a reasonable observer, that’s well over the line in terms of raising questions about the potential appearance of bias.

    And if there’s a question about appearance of bias, the obvious answer is: disclose. It is a shameful lapse of standards and ethics that the mainstream press failed to do that, and it misleads the readers.


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