A very interesting and novel study examining the effects of strongly nonlinear impact dynamics and unwarranted statistical extrapolations. A late entry, but the best paper I've read all year, hands down. Worth reading in its entirety including the acknowledgements.
https://www.bmj.com/content/363/bmj.k5094
This study is very suspicious: It doesn't appear to be blinded or double blinded. Did the participants know whether they had a parachute?
ReplyDeleteThere doesn't seem to be any control s in the unenrolled group! That will create a classic cass of "survival bias". Its possible parachute s are detrimental, but we can't tell unless some unenrolled people get backpack s.
Even knowing whether one is a researcher or subject should skew outcomes. Ideally some random amount of the participants should be convinced they are they researchers --- and then added to the unenrolled cohort , with backpack s. That should fix any of methodological bubbears.