I am pleased that Jeff Aronson has drawn attention to the potential
importance of anecdotes as evidence (1) and that he referred to Milos
Jenicek's important book on clinical case reporting (2). Another relevant
publication, which I regard as a classic, is Geoffrey Venning's 1982
cohort study of published case reports of postulated adverse drug
reactions (3). Venning showed that over half of these are confirmed in
subsequent research as likely to be real - a very strong tribute to
clinical acumen.
I have been trying since the 1980s (4) to draw Venning's study to the
attention of others, and to persuade them to consider replicating it, but
with only limited success (5). More than two decades have passed since
Venning reported his study in the BMJ. Perhaps those of your readers who
are unhappy about acquiescing in the fashionable view that anecdotes are a
very lowly form of evidence will help to clarify just how good or bad they
are by replicating Venning's study.
Iain Chalmers
1. Aronson JK. Anecdotes as evidence. BMJ 2003;326:1346.
2. Jenicek M. Clinical case reporting in evidence-based medicine.
2nd ed. London: Arnold, 1999
3. Venning GR. The validity of anecdotal reports of suspected
adverse drug reactions. BMJ 1982;284:249-252.
4. Chalmers I. Evaluating the effects of care during pregnancy and
childbirth. In: Chalmers I, Enkin M, Keirse MJNC, eds. Effective care in
pregnancy and childbirth. Oxford: Oxford University Press, 1989: 3-38.
5. Vandenbroucke JP. In defense of case reports and case series. Ann
Intern Med 2001;134:330-334.
Competing interests:
None declared
Competing interests:
No competing interests
29 June 2003
Iain Chalmers
Editor, James Lind Library
James Lind Initiative, Summertown Pavilion, Middle Way, Oxford OX2 7LG
Rapid Response:
Geoffrey Venning's classic BMJ paper
I am pleased that Jeff Aronson has drawn attention to the potential
importance of anecdotes as evidence (1) and that he referred to Milos
Jenicek's important book on clinical case reporting (2). Another relevant
publication, which I regard as a classic, is Geoffrey Venning's 1982
cohort study of published case reports of postulated adverse drug
reactions (3). Venning showed that over half of these are confirmed in
subsequent research as likely to be real - a very strong tribute to
clinical acumen.
I have been trying since the 1980s (4) to draw Venning's study to the
attention of others, and to persuade them to consider replicating it, but
with only limited success (5). More than two decades have passed since
Venning reported his study in the BMJ. Perhaps those of your readers who
are unhappy about acquiescing in the fashionable view that anecdotes are a
very lowly form of evidence will help to clarify just how good or bad they
are by replicating Venning's study.
Iain Chalmers
1. Aronson JK. Anecdotes as evidence. BMJ 2003;326:1346.
2. Jenicek M. Clinical case reporting in evidence-based medicine.
2nd ed. London: Arnold, 1999
3. Venning GR. The validity of anecdotal reports of suspected
adverse drug reactions. BMJ 1982;284:249-252.
4. Chalmers I. Evaluating the effects of care during pregnancy and
childbirth. In: Chalmers I, Enkin M, Keirse MJNC, eds. Effective care in
pregnancy and childbirth. Oxford: Oxford University Press, 1989: 3-38.
5. Vandenbroucke JP. In defense of case reports and case series. Ann
Intern Med 2001;134:330-334.
Competing interests:
None declared
Competing interests: No competing interests