2020.04.02 19:45:58 (1245769455004614656) from Daniel J. Bernstein, replying to "Jonathan Toomim (@jtoomim)" (1245498687360339969):
WHO's non-recommendation of parachutes for healthy skydivers predates the specific followup paper that you're talking about. Under the rules of evidence-based medicine, WHO has to recommend inaction (e.g., not wearing a parachute) unless there's clear evidence _for_ the action.
2020.04.02 20:00:39 (1245773151063044097) from Daniel J. Bernstein:
Of course, a new randomized clinical trial confirming the lack of effectiveness of parachutes helps the typical guided-by-intuition layperson understand how smart WHO has always been in never recommending parachutes for healthy skydivers in the first place.
2020.04.02 01:29:10 (1245493436939042816) from Daniel J. Bernstein:
Are you surprised to hear WHO saying that healthy skydivers don't need to and shouldn't use parachutes? This is backed up by a systematic review of randomized controlled trials, published in the British Medical Journal, cited more than 1000 times: https://www.bmj.com/content/327/7429/1459
2020.04.02 01:47:57 (1245498167275077632) from "Jonathan Toomim (@jtoomim)":
This metaanalysis is from 2003 and is out of date. You should try to always stick to up-to-date science. Parachutes were tested in an RCT in 2018 and were found to be no better than the control condition. https://www.bmj.com/content/363/bmj.k5094
2020.04.02 01:50:01 (1245498687360339969) from "Jonathan Toomim (@jtoomim)", replying to "Jonathan Toomim (@jtoomim)" (1245498167275077632):
Furthermore, the study found that parachutes were unreliable. Among the 12 participants in the intervention arm, the parachute failed to deploy properly for 12 (100%) of them.