4 ms·

Too slow to make the connection here... can you explain your reasoning?

jk563 7y ago
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 7y ago
  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 7y ago
    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.
goto11 7y ago
It seems to be a contrived joke: They tested people jumping with and without parachutes from a small airplane situated on the ground.
- pmyteh 7y ago
  It's a follow-up to a previous article bemoaning the lack of a randomised controlled trial of parachutes and arguing that they should not therefore be accepted as a valid 'treatment' for falling out of an aeroplane (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/). Both this article and its predecessor were published in the Christmas issue of the BMJ, where funny papers with a semi-serious point (in these cases, the ongoing debates in medicine about the superiority of RCTs over other forms of clinical evidence) are common. My favourite of this genre is "Does Peppa Pig encourage inappropriate use of primary care resources?" (https://doi.org/10.1136/bmj.j5397 https://doi.org/10.1136/bmj.j5397) critiquing the clinical practice of Dr Brown Bear, a fictional cartoon GP.
  - CrazyStat 7y ago
    My favorite BMJ Christmas article is a study of self-reported virgin mothers [1], but I might be biased because I know one of the authors. [1] https://www.bmj.com/content/347/bmj.f7102 https://www.bmj.com/content/347/bmj.f7102
- Ma8ee 7y ago
  Randomized studies of new treatments often exclude the sickest patients that could have benefitet most from the treatment. In particular, there won't be any really seriously ill patients in the control group because they will most likely die without treatment. That skews the results of these studies. This is what they try to illustrate with the jumping out of plane study. The result won't be reliable if you don't have a control group that actually might have benefit from the treatment. Cancer patients (jumpers), will or will not get a new type of chemotherapy (parachute). But since it is known that the sickest (hightest jumping hight) certainly will die without treatment (parachute), they decide to only test the treatment on patients with only early stage and benign cancer (close to the ground).

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 7y ago
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 7y ago
  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.

goto11 7y ago

It seems to be a contrived joke: They tested people jumping with and without parachutes from a small airplane situated on the ground.

pmyteh 7y ago
It's a follow-up to a previous article bemoaning the lack of a randomised controlled trial of parachutes and arguing that they should not therefore be accepted as a valid 'treatment' for falling out of an aeroplane (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/). Both this article and its predecessor were published in the Christmas issue of the BMJ, where funny papers with a semi-serious point (in these cases, the ongoing debates in medicine about the superiority of RCTs over other forms of clinical evidence) are common. My favourite of this genre is "Does Peppa Pig encourage inappropriate use of primary care resources?" (https://doi.org/10.1136/bmj.j5397 https://doi.org/10.1136/bmj.j5397) critiquing the clinical practice of Dr Brown Bear, a fictional cartoon GP.
- CrazyStat 7y ago
  My favorite BMJ Christmas article is a study of self-reported virgin mothers [1], but I might be biased because I know one of the authors. [1] https://www.bmj.com/content/347/bmj.f7102 https://www.bmj.com/content/347/bmj.f7102
Ma8ee 7y ago
Randomized studies of new treatments often exclude the sickest patients that could have benefitet most from the treatment. In particular, there won't be any really seriously ill patients in the control group because they will most likely die without treatment. That skews the results of these studies. This is what they try to illustrate with the jumping out of plane study. The result won't be reliable if you don't have a control group that actually might have benefit from the treatment. Cancer patients (jumpers), will or will not get a new type of chemotherapy (parachute). But since it is known that the sickest (hightest jumping hight) certainly will die without treatment (parachute), they decide to only test the treatment on patients with only early stage and benign cancer (close to the ground).