Current Anti-Doping Crisis: The Limits of Medical Evidence Employing Inductive Statistical Inference

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Vol.:(0123456789)
Sports Medicine
https://doi.org/10.1007/s40279-019-01074-0
EDITORIAL
Current Anti‑Doping Crisis: The Limits ofMedical Evidence Employing
Inductive Statistical Inference
PeriklesSimon1 · UlrichDettweiler2
© Springer Nature Switzerland AG 2019
1 Introduction
The anti-doping system is supposed to level the playing field
and protect clean athletes. Doping scandals of the past two
decades have seriously questioned the effectiveness of the
worldwide anti-doping program, and criminal investiga-
tions associated with those scandals have created evidence
for its partial ineffectiveness. However, legal action often
succeeded because of activities from within the anti-doping
community, such that the looming ineffectiveness could
still be interpreted as a sign of an isolated shortcoming of
the drug-testing program, while the overall “system of anti-
doping” was still effective and working. In other words, from
within the anti-doping system, we may not be able to assess
its own effectiveness.
In this situation, recent scientific investigations revealing
a high prevalence of doping in elite sports implicate inef-
fectiveness of the fight against doping in general and stress
the importance of independent anti-doping research activi-
ties [1]. However, these and other similar research activi-
ties investigate praxeological aspects of anti-doping. They
will depend on the level of independence and the level of
cooperation extended by organized sports to the scientists
involved, which will in turn limit the capabilities of such
research efforts.
In this issue of Sports Medicine, Heuberger and Cohen
publish a systematic review that could provide important
alternative directions for future anti-doping research [2].
The authors argue from an epistemological point of view
and question what constitutes a doping procedure in the first
place, and they challenge the methodological robustness
of medical evidence that has been generated to elucidate
performance-enhancing effects of doping substance classes.
We will use the opportunity of the unexpected outcome
generated by Heuberger and Cohen [2] to explicate the pos-
sibilities such purely non-praxeological analyses provide for
the anti-doping science community. The work of Heuberger
and Cohen [2] reminds us that it should in fact be scientists
who draw attention to the “more or less” scientific founda-
tion of anti-doping measures. Science is defined by the epis-
temological and methodological framework in which any
praxeology should be situated. We will thus argue that the
analysis of Heuberger and Cohen [2], especially those parts
that are controversial in nature, helps us to understand why
inductive reasoning, as employed by the authors, may not
represent the ideal basis for a Prohibited List.
2 Epistemological Allegation: The Very
Notion of(Medical) Evidence forFighting
Doping isChallenged
In 2012, the World Anti-Doping Agency (WADA) that
oversees the regulatory issues associated with anti-doping
set up an expert group that reported on the ineffectiveness
of the drug testing program [3]. Interestingly, this report
mentioned shortcomings in anti-doping only from a praxe-
ological perspective: “The primary reason for the apparent
lack of success of the testing programs does not lie with the
science involved.” is one of the central positions presented
in the executive summary and throughout all chapters of this
report. It is noteworthy that the practical aspect of doping
testing is a level WADA does not take direct responsibility
for. The report therefore leaves some room for questions to
be addressed by independent scientists. What is the very
nature of the science involved in anti-doping, from an epis-
temological and methodological perspective?
* Perikles Simon
simonpe@uni-mainz.de
1 Department ofSports Medicine, Faculty ofSocial Science
Media andSport, Johannes Gutenberg-University Mainz,
Albert-Schweitzer-Straße 22, 55128Mainz, Germany
2 Department ofCultural Studies andLanguages, Faculty
ofArts andEducation, University ofStavanger, Stavanger,
Norway

P.Simon, U.Dettweiler
Heuberger and Cohen’s contribution [2] falls into this cat-
egory of research, by assessing the clinical pharmacological
evidence for the performance-enhancing effect of doping
substance classes included in the Prohibited List. To put
the first key point of their analysis on the table, there is no
sufficient scientific evidence for 18 out of the 23 substance
classes. According to the WADA Code for a substance or
method to be added to the Prohibited List, these 18 sub-
stance classes could also be placed on the list if they ful-
filled both of the two alternative criteria, which are that they
represent an actual or potential health risk to the athletes
and that they violate the spirit of sports [4]. What about
“scientific evidence” for these other two criteria? This has
not been investigated by Heuberger and Cohen [2] and it is a
provocative question because there is and cannot be a means
to provide evidence for the extent of a violation of the spirit
of sports, and the WADA Code also does not imply this. For
ethical reasons, scientists’ abilities to generate evidence for
the harm aspect by virtue of randomized controlled trials
are even more strictly limited than testing for performance
enhancement. In other words, the list is thus for most parts
based on practical and ethical considerations, and not based
on scientific evidence in the classical sense. Again, it should
be noted that the WADA Code is only mentioning the word
“scientific evidence” with regard to the performance and
the harm aspect, and it does not explicitly state that such
evidence is required. The implications of this aspect will be
discussed in the following section.
3 Methodological Allegation: The Current
Level ofScientic Practice inAnti‑Doping
Science Needs Some Critical Revision
With their second key point, Heuberger and Cohen [2]
address a methodological aspect of the studies that presum-
ably demonstrated a performance-enhancing effect. Indeed,
the sample sizes of the sparse 11 studies that indicated the
performance-enhancing effect of five substance classes were
small and the statistical power was hardly comparable to
that of typical studies in clinical pharmacology. However,
this is only one part of the story because we could also ask
whether it is necessary or scientifically sound to apply clini-
cal pharmacological standards to the testing of performance-
enhancing effects of substance classes, as we argue below.
The review by Heuberger and Cohen [2] is partially reli-
ant on the outcome of a study by the same group that inves-
tigated the performance-enhancing effect of erythropoietin
(EPO) on cycling in a time trial and a typical mountain-
stage race [5]. Interestingly, their study conducted in the
typical fashion of a randomized controlled trial against
placebo failed to demonstrate an effect, while suggesting
effects on surrogate parameters of performance in the same
manner as other previous studies. Here, it should be noted
that mountain-stage races and cycling time trials are just two
of the many potential endurance-related outcome measures
that are of relevance to elite sports relying on various aspects
of the construct of endurance. Moreover, if these outcome
measures are not tested in an elite cohort subjected to factors
that typically accompany EPO use, such as losing weight,
as well as increasing the duration and intensity, and modi-
fying the structure of training sessions, how could they be
regarded as more valid outcome measures than, for instance,
maximal oxygen consumption or submaximal performance
traits related to lactate steady state measured in a laboratory
test? In other words, the EPO study by Heuberger etal. [5]
may have had an excellent internal validity but its external
validity might have been so low that a presumably negative
outcome should not be accorded great significance. Doping
experts in the field certainly are aware of some practical
advantages of administering EPO to cyclists.
The problem here is that Heuberger etal. [5] apply induc-
tive reasoning for verifying a performance-enhancing effect
of a very concrete doping procedure. This assumes that dop-
ers behave like patients who would subsequently receive
EPO prescribed under medical supervision. However, dop-
ers do not use EPO as tested by the authors. They use a more
creative concept of evidence and come to the conclusion to
use EPO at dosages never tested in clinical trials in combi-
nation with other blood-boosting agents such as insulin-like
growth factor 1, testosterone, and blood doping, and they
modify their living and training circumstances profoundly.
Thus, what is the point of conducting randomized controlled
trials to presumably test the performance-enhancing effects
of doping substance classes?
The rationale behind the concept of evidence is not
restricted to classical inductive statistical inference, as
Charles Sanders Peirce has pointed out [6]. He introduced
the concept of “abduction” into modern logic. Hereby, one
seeks to find the simplest and most likely explanation for
observations based on studying facts and devising a theory
to explain them. This discursive process, unlike deductive
reasoning or inductive (statistical) inference, yields a plau-
sible conclusion but does not positively verify it. Interest-
ingly, this is very prominent in criminology where conclu-
sions need be justified on often “purely” circumstantial
“evidence”.
4 Some Praxeological Perspectives
onAnti‑Doping Science: Present
andFuture
When considered at the praxeological level, the review by
Heuberger and Cohen [2] indicates that the scientific com-
munity dealing with anti-doping topics will now need to

Limits of Medical Evidence in the Current Anti-Doping Crisis
critically re-think the “evidence” involved in anti-doping
practice and research from epistemological and methodo-
logical perspectives. We argue here that it is not reasonable
to justify the Prohibited List on the basis of classical induc-
tive statistical inference. We should in fact reconsider more
critically the concept of conducting classical pharmacologi-
cal studies because their external validity will in any case be
low, or for most parts insignificant. Criminology is guided
by concepts and frameworks such as law systems, which
provide the basics for utilizing abductive reasoning, produc-
ing circumstantial evidence in a manner accepted by society.
Such a framework appears to be missing in the anti-doping
science field and we need to ask the anti-doping community
whether the Prohibited List should be based on more than
the ideas and interests of those who have the sports politi-
cal power. We envision that there is some work to be done
to level the playing field for compiling a Prohibited List in
the future.
We want to point out that inductive statistical inference is
nevertheless very essential for other aspects of anti-doping,
such as for instance the quality-control issues surround-
ing classical doping test procedures. A recent review has
drawn into question the general methodological robustness
of the drug testing program [7]. The scientific community
still refrains from presenting figures on the sensitivity and
specificity of drug testing. By applying proper statistics, it
is already evident that for certain testing procedures, such
as the present EPO testing, the test outcomes must comprise
a significant proportion of false-positive doping tests [7].
Here, more studies using inductive statistical inference and
displaying greater transparency with respect to study out-
comes are warranted.
In the future, science may need to address more rigor-
ously the serious epistemological and methodological
shortcomings in the anti-doping program. However, science
should also highlight persisting misinterpretation and false
communication of anti-doping measures that may endanger
the integrity of sports almost as much as doping itself. For
example, stating or implying that science would have pro-
vided evidence that the present anti-doping system is pro-
tecting the integrity of sports or the integrity of elite athletes
as individuals is an unfounded assumption. This has never
been shown.
Finally, we want to consider how the outcome of the
review by Heuberger and Cohen [2] could be disseminated
to the public. If we do not have classical pharmacological
evidence for a performance-enhancing effect for most of the
substance classes on the Prohibited List, would it not be the
first and most important obligation of the anti-doping system
to transport this message immediately to all athletes? As it
stands now, the Prohibited List may even serve as a blueprint
for persons who want to learn what might be performance
enhancing. We have to ensure we communicate that such
thinking is wrong. In so doing, we contribute to a preventive
measure the anti-doping community may not be exploiting
enough—harm reduction.
5 Conclusions
There is a lack of evidence for a performance-enhancing
effect of most of the substance classes in the Prohibited list
of WADA [2]. Here, we critically discuss why classical phar-
macological studies investigating monocausal drug–perfor-
mance relationships will most likely fail to deliver a valid
outcome. While patients are requested to follow treatment
regimens that have been shown to provide beneficial effects,
doping in elite sports will for most parts be conducted by
treatment regimens based on abductive inference. Doping
is variable in nature and often appears to involve the use of
multiple substances. It is adapted to the many accompanying
environmental factors, such as training, doping tests, and
body weight modifications, which can be highly specific to
a respective sport. Therefore, it appears to be reasonable to
consider under which circumstances it is more valid to apply
abductive instead of inductive statistical inference, to justify
why certain substance classes are placed on the Prohibited
List. Principally, evidence based on interdisciplinary and
transparent abductive reasoning within a still to be defined
framework could lead to a Prohibited List that serves both
analytical and preventive goals.
Compliance with Ethical Standards
Funding No sources of funding were used to assist in the preparation
of this editorial.
Conflict of interest Perikles Simon and Ulrich Dettweiler have no con-
flicts of interest that are directly relevant to the content of this editorial.
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