Null Hypothesis watch

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The abstract of a paper by Cynthia (CC) DuBois andDiane Whitmore Schanzenbach says,

This paper examines the effect of a court-ordered hiring guidelines intended to increase the share of black teachers employed in a school district in Louisiana. We find that the court-ordered hiring policy significantly increased the share of teachers who are black in the district relative to the rest of the state, and to a matched synthetic control sample. The policy also increased the share of new teachers hired who are black, and decreased the student-teacher representation gap, defined as the difference in enrollment share black among students and teachers in a district. There were increases in the share of black teachers observed in both predominately white and predominately black schools in the district. The policy had no measurable impacts—either positive or negative—on district-level measures of student achievement.

9 thoughts on “Null Hypothesis watch”

  3. Wow, love that abstract. I clicked through to make sure I understood it. Their analysis confirms: harsh racial discrimination in hiring during the treatment period strongly affects the racial composition of the workforce at the milestone date. Who woulda thunk it? But changing the race of the teachers did not make the young pupils any smarter! An astonishing result indeed. Obviously the authors need a bigger grant so they can look harder for more desirable effects.

  4. In normal economics, you would think that requiring more or a certain % of black teachers would have a negative effect on outcomes (assuming teacher quality matters at all), as it would require the school district to hire less than the most qualified teachers.
    So why isn’t that the result? To me that is the first interesting question, and the likely answer is problems with the study.

    The study cited by static is also interesting. Does it mean all schoolchildren are racist? If not, why do they do better with teachers of the same race? I doubt the accuracy of that study also, but maybe I am just being too hopeful.

    But assuming the study raised by static is correct, does it justify racial discrimination so that schoolchildren receive the best possible education? Do you fire long term black teachers as the student population become hispanic? Hire only white teachers for white children, only back teachers for black children and only hispanic teachers for hispanic children? Do we need to break out hispanics, as Mexicans do not care for Cubans. So only Mexican American teachers for Mexican American children?

  5. “In normal economics, you would think that requiring more or a certain % of black teachers would have a negative effect on outcomes (assuming teacher quality matters at all), as it would require the school district to hire less than the most qualified teachers. So why isn’t that the result? To me that is the first interesting question, and the likely answer is problems with the study.”

    “Normal economics” has little to do with educational outcomes, alas, and that’s not the most likely outcome.

    Considerable research has shown time and again that teacher’s cognitive ability (as reflected in test scores) has no impact on student outcomess.

    There’s more research showing that teacher race improves student outcomes (particularly black students, black teachers). So the odd news here is that student outcomes didn’t actually improve, but just remained the same. If I recall correctly, Goldhaber has found that black teachers who didn’t pass the Praxis have better results with black students than white teachers who have.

    Amazing, really, that the school lowered cognitive standards (presumably) yet got the same outcomes. Probably a good reason to hire black teachers in majority black districts, maybe lowering credential requirements.

    • Considerable research has shown time and again that teacher’s cognitive ability (as reflected in test scores) has no impact on student outcomes.

      There is a “range restriction” caveat here. In the pool of people who are smart enough and conscientious enough to get a college degree, “teacher’s cognitive ability (as reflected in test scores) has no impact on student outcomes.”

      • Yes, I’ve actually written about that before. It’s very likely that the lack of results means we’re above the basement, and that below the basement would in fact show that test scores matter.

        However, Goldhaber has found:

        Same-race matching effects dwarf most any information conveyed through the licensure test signal. We wish to point out that when teaching Black students, Black teachers in the lower end of the teacher test distribution are estimated to have impacts that are approximately the same as White teachers at the upper end of the distribution.

        In summary, we find that evidence suggesting the uniform application of licensure standards for all teachers is likely to have differential impacts on the achievement of White and minority students. Specifically, we see that Black and other minority students appear to benefit from being matched with a Black teacher regardless of how well or poorly that teacher performed on the Praxis tests, and these positive effects due to matching with Black teachers are comparable in magnitude to having the highest-performing White teachers in the classroom. Removing the lowest of performers on the exam would necessarily remove some of the teachers that appear to be most effective for this segment of the student population.

        • How does “race matching” impact whites and hispanics?
          How good is the study? What is the reason that the studies determine that dumb black teachers with black students do better than smart white teachers with black students? You are stating something is true that common sense says would be false. So a reason for the result would be interesting.

          • Aside from a course like calculus, having a smart teacher isn’t very important (I’m talking K-12 here). In fact, it can be a negative if the teacher “got” the subject easily and can’t get on the same level as her students.

            One of the most important things to realize about schools is that by grade 7, most students are not inherently interested in the subject matter. They are not there because they want to learn math or world history or biology (well, there is a subset of biology they are interested in). Perhaps the teacher’s biggest task is to get students to “engage” and try. A not terribly good black student is more likely to respond to a black teacher.

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