In other words (and more neutrally), there have not been any randomized controlled trials of parachute intervention, so we do not have data to say whether they would work or not.
This is satirizing the view of people who feel observational studies - studies in which everyone is treated with the experimental medicine and the response of the entire group is evaluated - aren’t clear enough or rigorous enough to prove that a drug works. True, these studies sometimes lack the clarity of a perfect randomized double-blind study, but as we see with the parachute, sometimes the results are pretty clear anyway. And in a life-or-death situation, no one wants to take the chance on a placebo. In other words, the “advocates of evidence based medicine” are being “challenged” with a little sarcasm. Inglis-Arkell 2014
In other words (and more neutrally), there have not been any randomized controlled trials of parachute intervention, so we do not have data to say whether they would work or not.
Imagine being part of that experiment.
“Here’s your parachute. Hope you aren’t part of the control group!”