[jk563]

The "Teacher Effects" paper is demonstrating that the value add to student achievment is likely noise and not representative of the teachers doing a better job.

The "Parachutes" paper is demonstrating that parachutes make no difference when used out of a stationary grounded plane.

I think the point is that both papers are demonstrating that the numbers alone don't tell the full story.

[jotakami]

The parachute paper says this, which I think is their “punchline”:

When beliefs regarding the effectiveness of an intervention exist in the community, randomized trials might selectively enroll individuals with a lower perceived likelihood of benefit, thus diminishing the applicability of the results to clinical practice.

So... was there some kind of selective enrollment in the teacher study? I don’t think that’s the issue here.

[iguy]

Sure, not the same mechanism (selective enrollment). But the papers seem parallel in that they try to demonstrate something we know to be crazy, using steps that are accepted when studying things we don't know.