Home > education, modeling, rant, statistics > The bad teacher conspiracy

The bad teacher conspiracy

August 29, 2014

Any time I see an article about the evaluation system for teachers in New York State, I wince. People get it wrong so very often. Yesterday’s New York Times article written by Elizabeth Harris was even worse than usual.

First, her wording. She mentioned a severe drop in student reading and math proficiency rates statewide and attributed it to a change in the test to the Common Core, which she described as “more rigorous.”

The truth is closer to “students were tested on stuff that wasn’t in their curriculum.” And as you can imagine, if you are tested on stuff you didn’t learn, your score will go down (the Common Core has been plagued by a terrible roll-out, and the timing of this test is Exhibit A). Wording like this matters, because Harris is setting up her reader to attribute the falling scores to bad teachers.

Harris ends her piece with a reference to a teacher-tenure lawsuit: ‘In one of those cases, filed in Albany in July, court documents contrasted the high positive teacher ratings with poor student performance, and called the new evaluation system “deficient and superficial.” The suit said those evaluations were the “most highly predictive measure of whether a teacher will be awarded tenure.”’

In other words, Harris is painting a picture of undeserving teachers sneaking into tenure in spite of not doing their job. It’s ironic, because I actually agree with the statement that the new evaluation system is “deficient and superficial,” but in my case I think it is overly punitive to teachers – overly random, really, since it incorporates the toxic VAM model – but in her framing she is implying it is insufficiently punitive.

Let me dumb Harris’s argument down even further: How can we have 26% English proficiency among students and 94% effectiveness among teachers?! Let’s blame the teachers and question the legitimacy of tenure. 

Indeed, after reading the article I felt like looking into whether Harris is being paid by David Welch, the Silicon Valley dude who has vowed to fight teacher tenure nationwide. More likely she just doesn’t understand education and is convinced by simplistic reasoning.

In either case, she clearly needs to learn something about statistics. For that matter, so do other people who drag out this “blame the teacher” line whenever they see poor performance by students.

Because here’s the thing. Beyond obvious issues like switching the content of the tests away from the curriculum, standardized test scores everywhere are hugely dependent on the poverty levels of students. Some data:



It’s not just in this country, either:

Considering how many poor kids we have in the U.S., we are actually doing pretty well.

Considering how many poor kids we have in the U.S., we are actually doing pretty well.


The conclusion is that, unless you think bad teachers have somehow taken over poor schools everywhere and booted out the good teachers, and good teachers have taken over rich schools everywhere and booted out the bad teachers (which is supposed to be impossible, right?), poverty has much more of an effect than teachers.

Just to clarify this reasoning, let me give you another example: we could blame bad journalists for lower rates of newspaper readership at a given paper, but since newspaper readership is going down everywhere we’d be blaming journalists for what is a cultural issue.

Or, we could develop a process by which we congratulate specific policemen for a reduced crime rate, but then we’d have to admit that crime is down all over the country.

I’m not saying there aren’t bad teachers, because I’m sure there are. But by only focusing on rooting out bad teachers, we are ignoring an even bigger and harder problem. And no, it won’t be solved by privatizing and corporatizing public schools. We need to address childhood poverty. Here’s one more visual for the road:


  1. JW
    August 29, 2014 at 9:34 am

    I agree with the sentiment of your article, but not so much the conclusion. You have only established here the correlation between poverty and test scores, not the causation. Replacing one statistical fallacy with another is not productive. If you have evidence that there is causation there, please share.


    • August 29, 2014 at 9:44 am

      You’re right. But I think we can agree that the statistics are not suggesting we blame individual teachers. Instead we should look at the relationship between poverty and test scores.

      It is of course a complicated relationship, and historical. And teachers should be our allies on this exploration, not our enemies.


      • JW
        August 29, 2014 at 10:33 am

        I could not agree more. I think blaming teachers is Very Clearly unwarranted. I think the problem really needs more study to clearly understand NOT where the blame lies but in what we can do to improve the situation. While I think there is quite a bit of good research on the causes of under-performance, there needs to be much more done.

        Assigning to blame to poverty is every bit as statistically unwarranted as assigning the blame to teachers.


  2. lindapbrown2013
    August 29, 2014 at 9:45 am

    I especially appreciated your why-bad-journalists-are-responsible-for-newspapers-dying analogy. Here is a well-known essay comparing teachers and dentists in poor and middle-class communities.

    Thank you so much for continuing to care and write about this issue!



    • August 29, 2014 at 9:48 am



    • Guest2
      September 2, 2014 at 10:58 am


      So — why aren’t teachers at the forefront of income equalization? This is what got Ruby Payne active on this issue. She seems to be the only one that recognizes the problem and it willing to do something about it.


  3. August 29, 2014 at 9:53 am

    Reblogged this on Network Schools – Wayne Gersen and commented:
    I was going to write a post on this… but I hereby surrender to the Mathbabe. She does a GREAT job eviscerating the arguments implicit in this article. BTW, as noted in an earlier post, there IS no tenure! http://waynegersen.com/2014/08/19/there-is-no-tenure/


  4. August 29, 2014 at 9:54 am

    OUTSTANDING evisceration of the article’s premise. One bone to pick, though, in public education there is no tenure per se. For more: http://waynegersen.com/2014/08/19/there-is-no-tenure/


  5. August 29, 2014 at 12:41 pm

    Deciding what counts as “proficient” performance on a test is actually a highly arbitrary and highly politicized decision. Good reading on how the cut scores to determine proficient vs non-proficient here:


    Anthony Cody sums the issue up well: “Standardized tests are a political weapon and can be used to tell whatever story you want. The campaign to hold schools and teachers “accountable” for test scores is a political project designed to deflect responsibility away from people who have gotten obscenely wealthy over the past few decades. The concept of “failing schools” is a bogus one. Schools are being shut down not in the interest of the children who attend them, but in order to create opportunities for new players in the education marketplace.” http://blogs.edweek.org/teachers/living-in-dialogue/2013/08/from_school_grades_to_common_c.html


  6. August 29, 2014 at 1:45 pm

    “bad teachers have somehow taken over poor schools everywhere and booted out the good teachers.”

    You’re joking, but surely some of this IS happening. Teachers are more likely to leave under-funded schools with poor leadership, poor working conditions and commutes through undesirable neighborhoods. There are also issues of demographic mismatch between students/teachers which presents all sorts of other issues. This paper by Helen Ladd gets into some of this (sorry, it’s not free) http://epa.sagepub.com/content/33/2/235.short

    In the very least, there would be a teacher turnover issue at poor schools. Regardless of how we define good/bad in education, It stands to reason that ‘good’ teachers are better able to leave ‘bad’ schools or simply leave the profession altogether.


  7. August 29, 2014 at 2:11 pm

    Agree strongly with JW that correlation is not causality.

    But now let’s look at the problem from a data science perspective.

    Free lunch does not equal poverty when there is no system of verification, and certainly not in a city with a social net like NYC, where the real squeeze is on the families that are not poor enough to qualify for the social net, yet are not rich enough to handle the high cost of living in this expensive city.

    Looking at the mean without looking at the variance (let’s ignore the higher moments like skew and kurtosis) makes for a pleasing graph, but ignores the variability among the poor. It ignores factors like culture or history. It’s like using principal factors when the factors aren’t independent or orthogonal. Or like using principal components and naming the component “poor,” when in fact the contribution of “poor” to the component is less than full.

    Now let’s look at the concept of bad teachers. Anecdotally I observed that bilingual math teachers in NYC schools are on average not as good as math teachers without the bilingual designation. That is, they were hired mainly because of their ability to teach in another language, rather than their ability to teach math per se. Assuming for a moment that bilingual students meet the definition of “poor,” then they are more likely to have less qualified teachers for math if they are forced into bilingual classes (as they usually are – for POLITICAL reasons).

    There is a tendency for some good teachers to give up on the bureaucracy of the NYC DOE, and flock to the richer suburbs where the pay is also higher.

    I am most grateful that I was taught math in my third, but dominant, language (English) and that nobody tried to force me to learn math in Hungarian. In fact, when I do arithmetic in my head, in the three other languages I am fluent in, I take two extra clock cycles: translate problem to English, [compute in English], translate result to other language.

    I am all for learning and mastering other languages, but it should not come at the expense of mastery in important subjects.

    On the VAM model, I am in total agreement with Cathy. However, I would shift the adjective “toxic” to Common Core. It’s nice if students can “discover” math on their own, but it’s even better for the majority of students if they are given a solid foundation on which to build those “discoveries.”


    • GPE
      August 30, 2014 at 3:29 pm

      Concur on the causation/correlation argument. I would also like to see the data behind the graphs and better understand how “poverty” is being defined. The school lunch program is an increasingly poor dimension upon which to base such a definition. Google “free school lunch for all students” to find a growing number of school systems that are electing to offer free lunch for all students for reasons such as:

      “School officials say that the program is beneficial because no student feels singled out because of their economic situation.”

      Ref: http://www.kentucky.com/2014/08/11/3375380_federal-program-will-fund-free.html

      Regardless how one feels about this trend, it’s masking the underlying problems.


  8. August 29, 2014 at 4:51 pm

    Reblogged this on The Art of Teaching Science and commented:
    As Dr. O’Neil states in her article, standardized test scores everywhere are hugely dependent on the poverty levels of students. This combined with tests that are not related to the curriculum creates a miserable situation for teachers and students.


  9. pjm
    August 29, 2014 at 6:39 pm

    I think it factually correct to say causation is not casuality and in the “human” sciences casuality can be a really complicated thing. But the causality/correlation dichotomy is not so crucial in a situation where there are not many (or any) plausible alternative hypothesis or where there is other evidence of a mechanism between the correlated variables. In the education debate, the issue is not that poverty adversely effects educational achievement (which almost all reasonable persons in the debate conceed) but what the relative effect of poverty compared to other factors.


  10. NS
    August 30, 2014 at 4:48 pm

    Education is one of those few topics which generally divides the left along racial lines with minorities, mostly black and latino, on the other side from whites (on the left) and teachers.

    I suspect, but am not sure, that it is due to “white privilege” playing out. Whites have always had better schools and teachers than others racial groups so they tend to blame educational performance on issues outside of schools such as poverty and parental involvement. While those of us who have been to inner city schools and have had first hand experience with terrible teachers know otherwise. I went to a public school in LA and had teachers who came drunk to class, masturbated in class, and were blatantly racist. This is not even touching on their knowledge of subject matter or their ability to impart it to students. Of course this impacts the academic performance of students and to blame it all on the family is blatantly racist.

    The data analysis does not prove that teachers don’t matter. It could be simply that the quality of teachers is correlated to poverty.


    • pjm
      September 1, 2014 at 12:03 pm

      I am a new teacher but have been following the education debates for a long time (decades). I recently spoke to a teacher who had done a couple years in the NYC public schools and discussed the lack of resources and demoralization. And THEN in the next breath said something snarky about tenure protecting the bad teachers. Uh, disconnect much?

      Bad teaching does matter but so does lack of material support. Poverty and bad teaching do have a causal link:

      lack of resources mean teachers don’t get professional support and don’t improve (which is something all teachers need and, btw, the US is known for relatively low levels of professional support for teachers generally)

      lack of resources mean the kids are harder to teach and often feel disrespected by the run down condition of their schools. The kids are pretty smart in this respect.

      bad teachers tend to congregate in urban schools, because they have more job security precisely because the good teachers are demoralized but have options and leave.

      But making tenure or teacher professionalism the center of educational reform is at best misplaced and often is deeply cynical.


      • September 1, 2014 at 12:20 pm

        Can you please elaborate on what resources the NYC teacher was lacking? Did the teacher ask the principal for said resources and was denied? The per-pupil allocation in NYC public schools is quite high compared to other public schools. Accountability in certain schools could be a problem.


  11. August 31, 2014 at 9:23 am

    Mathbabe – suggest a peek at Econtalk episode http://www.econtalk.org/archives/2013/08/hanushek_on_edu_3.html especially starting at 30:48. Commentary that replacing the very few teachers that all in a position to know at a particular school agree should not be retained would vault the US in the PISA/Relative Poverty score above Canada. Thoughts? From anyone?


  12. September 1, 2014 at 12:20 pm

    Reblogged this on Destroyer of Exoplanets and commented:
    The problem with blaming tenure…


  1. September 3, 2014 at 4:44 pm
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