Satire of evidence-based medicine from BMJ:
What is already known about this topic
- Parachutes are widely used to prevent death and major injury after gravitational challenge
- Parachute use is associated with adverse effects due to failure of the intervention and iatrogenic injury
- Studies of free fall do not show 100% mortality
What this study adds
- No randomised controlled trials of parachute use have been undertaken
- The basis for parachute use is purely observational, and its apparent efficacy could potentially be explained by a “healthy cohort” effect
- Individuals who insist that all interventions need to be validated by a randomised controlled trial need to come down to earth with a bump
This is really funny stuff. Check this out:
One of the major weaknesses of observational data is the possibility of bias, including selection bias and reporting bias, which can be obviated largely by using randomised controlled trials. The relevance to parachute use is that individuals jumping from aircraft without the help of a parachute are likely to have a high prevalence of pre-existing psychiatric morbidity. Individuals who use parachutes are likely to have less psychiatric morbidity and may also differ in key demographic factors, such as income and cigarette use. It follows, therefore, that the apparent protective effect of parachutes may be merely an example of the “healthy cohort” effect.
It is often said that doctors are interfering monsters obsessed with disease and power, who will not be satisfied until they control every aspect of our lives (Journal of Social Science, pick a volume). It might be argued that the pressure exerted on individuals to use parachutes is yet another example of a natural, life enhancing experience being turned into a situation of fear and dependency. The widespread use of the parachute may just be another example of doctors’ obsession with disease prevention and their misplaced belief in unproved technology to provide effective protection against occasional adverse events.
[hat tip: Freakonomics]