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# Adverse events in British hospitals: preliminary retrospective record review

BMJ 2001; 322 (Published 03 March 2001) Cite this as: BMJ 2001;322:517

## Rapid Response:

### Quick Risk Comparison

If, say, 10% of all admissions to medical facilities lead to an
adverse event,and say, 10% of these result in a fatality, then the chance
of death due to such an event is one in a hundred per person-admission (or
treatment). That is, a probability of 0.01 on average (often expressed
mathematically as 1E-02).

If a train commuter was exposed to the same risk as this due to
adverse events on the railways, then the result would be a fatality rate
of one per hundred passenger-journeys. Thus if the commuter made, say,
twenty journeys per month, his life expectancy would be about five months
(slightly longer than a Battle of Britain fighter pilot). This would
quickly put paid to rail travel.

In fact the chance of dying on a rail journey equates to about 1
fatality per 500,000 passenger-journeys or a probability of 0.000002 often
expressed as 2E-06. Travel by car doubles this risk per journey, and by
air the risk is about 6 times greater per journey than by rail (note that
aviation safety statistics are massaged to look better by using a
kilometre travelled basis to calculate the risk, comfirming most people's
gut feeling that air travel is inherently risky!).

Crudely stated, the chance of dying as a result of entering hospital
is therefore 5000 times greater than on entering a train (2500 times worse
than by car and about 1000 times worse than by aircraft per journey).
Given all the recent negative publicity about rail safety, this comparison
provides, to say the least, cause for reflection on the reasons for

What happens in a hospital to make it such a dangerous place compared
with a train (car, aircraft, etc)?

I am currently writing a book about fatal accidents resulting from
human error, including medical errors (or adverse events),but in
particular looking at the system faults which lead to errors (so-called
systemic or system induced errors).

Any suggested answers to the above question would be most welcome.

Barry Whittingham

Competing interests: No competing interests

08 April 2001
Barry Whittingham
Risk Consultant
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