This is probably not the “simplest” explanation I could give, but I find it memorable. I heard this story in college, but haven’t looked for the reference.
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There was apparently once a study for a new medication, which the researchers really thought would work. So they went through the whole process of a randomized trial, and it came back with no result. The medicine didn’t help.
They thought about this for a while, and then wondered if maybe the problem was that people weren’t taking the medicine regularly enough. Perhaps people were skipping days, or taking it at different times every day, and this was screwing things up? So they re-ran the study, this time tracking compliance. And lo and behold, people who regularly took the medicine did indeed do better than average!
As good scientists, however, they applied the same analysis to their placebo tests. And they found that people who regularly took the placebo also did better than average.
It turns out that the medicine was indeed worthless, but that the sort of people who remember to take their medicine every day are just generally healthier, because they are more likely to be concientious and do things like exercise and eat well.
This is probably not the “simplest” explanation I could give, but I find it memorable. I heard this story in college, but haven’t looked for the reference.
~~~
There was apparently once a study for a new medication, which the researchers really thought would work. So they went through the whole process of a randomized trial, and it came back with no result. The medicine didn’t help.
They thought about this for a while, and then wondered if maybe the problem was that people weren’t taking the medicine regularly enough. Perhaps people were skipping days, or taking it at different times every day, and this was screwing things up? So they re-ran the study, this time tracking compliance. And lo and behold, people who regularly took the medicine did indeed do better than average!
As good scientists, however, they applied the same analysis to their placebo tests. And they found that people who regularly took the placebo also did better than average.
It turns out that the medicine was indeed worthless, but that the sort of people who remember to take their medicine every day are just generally healthier, because they are more likely to be concientious and do things like exercise and eat well.
Wow, that’s really good! It was worth making the post just to hear that story.