# Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials

*Smith & Pell · Measurement & Method, Critique & Boundary · BMJ · 2003 · Open access*

A satirical paper in the BMJ written in the form of a systematic review. Smith and Pell searched Medline, Web of Science, Embase and the Cochrane Library for randomised controlled trials of parachute use, set out a planned analysis with odds ratios, heterogeneity tests and a funnel plot, and found no trials to analyse. The discussion keeps a straight face: parachute use is itself associated with morbidity and mortality, free fall without one does not inevitably end badly, and the apparent protective effect may be merely a healthy cohort effect, since those who jump without a parachute are, they suggest, likely to carry more psychiatric morbidity. It also cites a real reversal, hormone replacement therapy, where observational studies showed an apparent protective effect on ischaemic heart disease and randomised trials showed increased risk. It closes on two options: accept that under exceptional circumstances common sense might be applied, or preclude parachute use outside a properly conducted trial, for which, they feel assured, advocates of evidence based medicine will not hesitate to volunteer.

Its target, in its own words, is individuals who insist that all interventions need to be validated by a randomised controlled trial; the paper leaves its exceptional circumstances undefined, argues by absurdity and has no data of its own. The bridge to psychological safety is ours. Tom uses it against the demand that psychological safety prove itself through a randomised controlled trial before it is taken seriously, while holding that the argument covers the mechanism, not the company survey, the stage model or the dashboard metric.

- **This page:** https://explore.psychsafety.com/n/smith-pell-2003/
- **View the source paper:** https://pmc.ncbi.nlm.nih.gov/articles/PMC300808/
- **Interactive map:** https://explore.psychsafety.com/?mode=papers&node=smith-pell-2003

## Neighbours (3)

- [Parachutes & Evidence](https://explore.psychsafety.com/n/parachutes-and-evidence-based-thinking.md)
- [When are randomised trials unnecessary? Picking signal from noise](https://explore.psychsafety.com/n/glasziou-et-al-2007.md) (paper)
- [Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial](https://explore.psychsafety.com/n/yeh-et-al-2018.md) (paper)