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Web Site
Entry For High School Teachers And College Statistics Professors
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Your
feedback is welcome:
email@improvingmedicalstatistics.com
The focus of this web site is
how the use of medical statistics and the interpretation of studies in the medical
literature can be improved. The
approach employed is to evaluate individual studies where the statistical
analyses have
been poorly performed or have conclusions that are poorly formulated.
A downloadable file of materials from this site
is available as noted at the top of this page. (It would be very
useful in addition to obtain the original complete study that is being
critiqued. However, most of these are available only through a medical
library.)
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WEB SITE
TOPICS OF POTENTIAL INTEREST FOR HIGH SCHOOL & COLLEGE EDUCATORS:
This
site contains material that can be used in a high
school or college introductory
statistics course as a source of case studies from the medical literature
Download
of selected topics and case study information:
Download
(90kb)
The
cases most accessible on this web site for high school and college
statistic courses are likely to be the following:
1. An example of a completely invalid statistical analysis in the
medical literature. In this study in a major medical journal, despite a study
involving high
powered diagnostic testing involving P.E.T. scans, the statistical
analysis is completely off base.
(i.e. One cannot take two groups and subdivide one of those groups on the basis of
high and low values of a certain characteristic, and then say that the two
initial groups are different just because the subdivided group with low values
of the characteristic differs from the group that was never subdivided).
A statistical analysis in a major medical
journal JACC (Journal of American College of Cardiology) which was so bad,
that it may have led to a subsequent improvement in the review process of JACC.
2.
There is a New England
Journal of Medicine article that shows failure in all regards –
interpreting data, execution of the trial, incorrectly counting data, and potentially being at
risk for a type II statistical error. This may also be of value. A study in the New England Journal of Medicine where the conclusions
run exactly the opposite of what the data suggests.
The authors after publication then subsequently determine they
had unintentionally miscounted their primary data endpoints. In this one study, the authors
miscounted their trial's primary endpoints, included patients that did not belong in
the trial, then incorrectly analyzed the data with a potential for a Type II statistical error,
and finally failed to appreciate the implications of their miscounted data
(a grand slam for a poorly conducted and interpreted trial).
3.
The underpowered study, how a type II error can occur.
Death
of the oat bran fad. (Murdered by a poorly conceived study.)
The subsequent meta-analysis published
by one of the authors of the initial suboptimal oat bran study is a classic
example of how the conclusions of a meta-analysis can be biased. case
study of biased meta-analysis conclusions
4.
There is also an article that is not a
clinical study but rather Peter Sleight’s (a leading medical investigator in
England) comments about
the hazards of subgroup analysis in medical trials. This is a insightful
article and a wonderful presentation of this subject. The Hazards of Subgroup Analysis (Are
Geminis really different?)
5. There is also an area that talks
of how the medical literature self corrects over time. This may or may not be of
interest. The Reparative Power of
Science:
Revisit these controversies
"10
years
later"
6.
Not for your students, but of potential interest to you, is a whole section on the
limitations of a
meta-analysis and the potential strengths and weaknesses of large randomized
clinical trials. A meta-analysis is often assumed to be a
definitive word on a clinical topic by the media as well as some in the field of
medicine. This
is certainly not always the case. The information in this area helps in
understanding one of the reasons for variability in the medical literature.
Limitations
of Meta-Analyses
A meta-analysis adds similar smaller
trials together in an attempt to better assess the effects of a treatment.
Often a meta-analysis is thought of as the final word concerning a medical
topic. A topic that receives relatively little attention today regards potential
weaknesses of meta-analyses.
The Very Large Randomized
Clinical Trial (Strengths and Limitations)
(This type of trial is increasingly
and appropriately used to make recommendations on how to treat patients.
Information on recognizing a well conducted large
trial is presented.)
A Tale of Two Large Trials
A recent stellar large clinical trial is compared to a large
clinical trial with poorly formulated conclusions. Both these trials effect current treatment guidelines for
patients.
Beware of
Meta-analyses bearing False Gifts
A meta-analysis written by a strong proponent
of one side of a controversy is particularly problematic.
Download of selected case studies of inappropriately interpreted clinical trials
(90kb)
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