They found some volunteers and did the study! This is one of the classics from the Christmas BMJ: https://www.bmj.com/content/363/bmj.k5094 https://www.bmj.com/

They found some volunteers and did the study! This is one of the classics from the Christmas BMJ: https://www.bmj.com/content/363/bmj.k5094 https://www.bmj.com/content/363/bmj.k5094 The study has... let's just say "other methodological problems". But they did do an RCT of parachute use! (The open peer review correspondence is quite fun, too).