Bias, confounding, short-termism and inaptness: does medical research trump banking?
The research paper by Firth, Zheng and Biller (1) on coin ingestion
and the recent sharp reduction in societal wealth caused by shortcomings
in the banking system is both insightful and timely. It sheds a welcome
degree of lightness on the current creditectomy induced recession gloom.
However, their study suffers from a number of shortcomings. These should
be considered carefully because, as with banking, shortcomings in medical
research have also resulted in taxpayers’ billions being spent on
questionable societal w(h)ealth protection measures (2,3). The first three
shortcomings of the study by Firth and colleagues are methodological, the
last is related to relevance.
First, the authors claim the study is valid. However their discussion
of this issue is restricted to the question of internal validity. It does
not address external validity. The sample is taken from patients
presenting at a leading teaching hospital in pre ‘Obamacare’ America. This
means that the unemployed, uninsured strata of society will have been
severely under-represented. This referral bias is worrying and leads one
to think that the value of the study would have been much enhanced if it
had been conducted in a socially unbiased hospital setting, such as that
pertaining in the NHS. Yet another example of the superiority of the NHS
over the American health care system.
Second, the authors point out that the Credit-card-use-by-Default
Swap for cash (CDS) obligation imposed on households by the credit crunch
is a potential confounder. But the authors make no attempt to account for
CDS behaviour in their analysis. As with bankers, this is probably due to
a poor understanding of the toxic effect of CDS and its derivatives on,
for example, regurgitation of bodies swallowed (RBS) and other equally
unattractive savings options.
Third, there may be a long-term impact of the risk factor on
paediatric coin ingestion that is not taken into account by this three
year observational study. A longitudinal prospective study will be needed
to determine how the risk factor impacts on the survival of the greediest,
and how this is translated into the natural tendency of future paediatric
generations to inherit more greedy characteristics, thereby increasing the
incidence of coin ingestion.
Finally, perhaps the major shortcoming of this paper is its
questionable aptness for the Christmas edition of the BMJ. In short the
paper provides a limited stimulus package. Firth and colleagues may have
brought a smile to the faces of some readers. For most subscribers,
however, this year’s Christmas cheer will not have been stimulated at all
by reminders about the excess haemorrhaging of their savings and pension
funds resulting from the risky operating procedures followed blindly by
bonus blinkered bankers.
In summary therefore, while Firth et al poke oblique fun at bankers,
they should perhaps be a little bit reticent about the medical
researchers’ pot calling the bankers’ kettle black.
(1) Firth PG, Zheng H and Biller JA. Ingested foreign bodies and
societal wealth: three year observational study of swallowed coins. BMJ
(2) Godlee F, Clark M. Why don’t we have all the evidence on
oseltamivir? BMJ 2009;339:b5351
(3) Jack A. Flu’s unexpected bonus. BMJ 2009;339:b3811
Competing interests: No competing interests