“Per protocol analysis” is when medical trial researchers drop people who didn’t follow the treatment protocol. It is outrageous and must be stopped.

For example: let's say you want to know the impact of daily jogs on happiness. You randomly instruct 80 people to either jog daily or to simply continue their regular routine. As a per protocol analyst, you drop the many treated people who did not go jogging. You keep the whole control group because it wasn’t as hard for them to follow instructions.

At this point, your experiment is ruined. You ended up with lopsided groups: people able to jog and the unfiltered control group. It would not be surprising if the eager joggers had higher happiness. This is confounded: it could be due to preexisting factors that made them more able to jog in the first place, like being healthy. You’ve thrown away the random [...]

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First published:
January 31st, 2024

Source:
https://www.lesswrong.com/posts/6xdYcWiojsGsnfcPy/per-protocol-analysis-as-medical-malpractice

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“Per protocol analysis as medical malpractice” by braces

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“Per protocol analysis as medical malpractice” by braces