The whole point of the study is to show the limitations of a Randomized Controlled trial. This study shows the difficulty in studying the effectiveness of entr

The whole point of the study is to show the limitations of a Randomized Controlled trial. This study shows the difficulty in studying the effectiveness of entrenched practices, especially when there is good reason to suspect that not using the practice will result in extremely significant harm at high probability. Here we have a study with enormous self-selection bias. They did ask candidates mid-flight in commercial aircraft if they would be willing to participate at their current altitude and speed, and obviously all declined. On the other hand a number of candidates found on private planes that were not moving were willing to participate. This study also shows how statistical techniques can be misused, as here in a study where the adverse results in question occurred in literally zero participants of the control group is obviously worthless, but one can still run the stats to conclude no statistically significant difference was detected. Lastly it brings up questions about best available evidence. Many researchers tend to automatically assume that an RCT is better than other evidence. Now if they read the study closely and notice flaws they often change their mind, but if they just skim the abstract they can miss this. This is an example of a case where the only available RCT is total garbage, and we have far better evidence in the form of accident statistics from skydivers. Accidents where no chute was packed, or the chute (and any backups) completely fail to deploy are a very good proxy in practice for jumping without one at all.