An Interview with Michael Hansen: School System – Move those Kids Around!

Dec 5, 2013 by

Michael F. Shaughnessy –

1) Michael, recently you were asked to perform a kind of statistical analysis on some data from North Carolina. How did this come about?

Staff at the Thomas B. Fordham Institute had heard of these ideas trying to expose more students to stronger teachers as a way to improve education. They called me asking about any studies that actually produce evidence on this; there weren’t any looking at this question specifically, so they asked if I’d be interested in taking on the task. This hasn’t been done on a broad scale (that I know of), so I had to construct a simulation.

2) Apparently North Carolina assigns pupils based on teacher effectiveness. How do they go about this?

To clarify your statement, it appears there is a very slight tendency to assign pupils based on effectiveness—so there’s still a lot of room to improve. Another study in Kentucky has also found similar assignment patterns. As for how this happens, I don’t know; that information is not contained in the administrative data used for the study, I’m just reporting what I can observe.

3) Apparently your most effective teachers are going to have larger classes, and the least effective teachers get smaller classes. What are the results?

That’s exactly right – this assignment pattern maximizes overall student learning. I find if the strongest teachers were assigned up to 12 additional students in their class (compared to the average in the same school and grade), learning in 8th grade math and science could increase by an amount equivalent to an extra 2.5 weeks of instruction. Even reallocating just six students results in nearly 2 extra weeks of learning. The results in 5th grade were considerably smaller: even the largest shifts considered in the paper only yielded an extra two days’ worth of learning.

4) It seems that very minor tweaking results in very major growth patterns- or am I off on this?

Correct – small changes in current practice may yield some important gains, particularly in 8th grade. In the paper I talk about results if only three or six additional students were assigned to stronger teachers. These levels of class size shifting are noteworthy because I already see class-size differences around this size in the data. So, it’s not hard to believe that we could get some modest gains for basically nothing – it just requires schools to simply be more strategic in the way they go about assigning class sizes to teachers.

5) Can you compare changes at the 5th grade and 8th grade level?

I’m glad you asked. The results were much larger in 8th grade than they were in 5th grade.

I speculate the most likely reason for this is because of the self-contained classrooms that are standard practice in 5th grade..”

– they make it more difficult to reliably pick the stronger teacher when performance is averaged across noisy measures in three subjects.

Presumably this is where principals’ extra information on teacher performance would really come in handy to supplement the value-added measures that were the only measures I could use (because of the nature of the data).

6) This could be termed  “class size shifting”. Is there a way to consistently do this?

Yes, the easiest way to do this is to reallocate kids from the weakest teacher’s classroom to the strongest teacher’s classroom. How many kids should be moved? A number proportional to the difference in what we might reasonably expect between the teachers. If this difference between the teachers is small, just move 1 or maybe 2 students. Conversely, if the difference between the teachers is large, there is more to gain by moving more students, up to 12 or more. But before you do so, it’s advised to make sure the stronger teacher is willing to accept the extra kids.

7) Now can this help the kids in real poverty stricken schools ?

Sure it can. The distribution of teachers in those schools is not nearly as different as many people assume. If we give their stronger teachers a disproportionate share of the kids, we expect to see gains there just like we see in other schools.

8) What about persistently ineffective teachers- and yes, I have heard about teachers who show movies in every class, every day.

This approach to determining teachers’ class size reduces the size of the weakest teachers’ classes (minimizing students’ exposure to them). Hopefully most teachers in this group can leverage an opportunity like this to genuinely improve their instruction.

9) What about the achievement gap? Will this maneuver of moving those kids around help different racial or ethnic groups?

This is an important question. This strategy alone will not likely reduce the achievement gap because it only increases students’ access to the strongest teachers in their school. Because schools serving high-need student populations tend to be at a disadvantage in courting and keeping the best teachers, there’s a limit to how much their students will gain. To state this another way: all students can gain greater access to effective teachers in their school under this strategy, but a gap in access reflecting differences in teachers across schools will still remain.

10) What have I neglected to ask?

Larger classes sound like a punishment and smaller classes sound like a reward – isn’t your proposal setting up a perverse incentive actually encouraging teachers to be ineffective?

It does if we continue to pay all teachers the same amount, which is obviously unsustainable. However, if districts were to compensate teachers somehow for the extra kids (e.g., bonuses, additional teaching support, preferential treatment in determining other non-classroom work), I think there’s a way to make incentives under this approach consistent with promoting effective teaching.

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