Klaas Faber 0

Thresholds to prevent questionable doping convictions

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Numerous convictions for doping offences are possibly inconsistent with WADA’s Criteria for including substances and methods on the Prohibited List, see fragment of the 2009 World Anti-Doping Code below, and therefore questionable. Basic logic dictates the introduction of thresholds (=maximum allowed levels) for substances that are prohibited in-competition only because of their short-lived effect. You may think of 'party drugs' like stimulants and cannabis.

A rational distinction can be made between tests that are 'positive' due to:

1. in-competition use,

2. out-of-competition use (often days or weeks before an event), or

3. accidental contamination.

Obviously, WADA’s criteria are intended to cover the first case: in-competition use (criteria and specifically mention Use). However, it is accidental contamination in particular that leads to regrettable victims of an inconsistency that is easily solved.

Let us turn attention to three questionable convictions:

1. Level=42 ng/ml. The Swiss tennis player Martina Hingis could not provide an explanation for a 'positive' cocaine test and was subsequently convicted to a two year suspension.

2. Level=151 ng/ml. The French tennis player Richard Gasquet attributed his ‘positive’ cocaine test to him kissing a woman that had used the drug. Mr. Gasquet was sentenced to two months and 15 days.

3. Level=1300 ng/ml. The Dutch gymnast Yuri van Gelder confessed to having used cocaine three days before the ‘positive’ test and received a one year ban.

The level obtained for Mr. van Gelder, which obviously had no effect on his performance just before the test, implies that the levels detected for Ms. Hingis and Mr. Gasquet are totally irrelevant in the context of doping. Two quotes follow that further illustrate the grave injustice most likely done to Ms. Hingis.

From an article by Aaress Lawless (see Links): "Unfortunately, for Hingis, the very locale where the drug test was administered has become a cocaine residue breeding ground. The UK’s Telegraph reported in 2005 that London’s ThamesRiver was awash in cocaine, as over 150,000 lines of the recreational drug were smoked each day. Cross contamination has permeated through the water, restrooms and even bank notes."

From an article by Jon Wertheim (see Links): "Though never directly attributed to the peculiarities of her case, curiously, in the months after her hearing, rules were altered and administrators were given latitude to dispense suspensions of any length from zero to two years."

Clearly, the problem is that athletes are currently prosecuted regardless the amount of substance detected. With instruments' sensitivities continuously improving, the amounts leading to a ‘positive’ test often reach a level where WADA's Criteria are not satisfied. N.B. The current reasoning does not apply to substances that are forbidden at all times, i.e. both in-competition and out-of-competition. For that category of substances, e.g. exogenous anabolic steroids, the athlete is always liable.

Basic logic dictates that thresholds would enable one to differentiate between relevant and irrelevant amounts. These thresholds should be functionally motivated, i.e. not based on instrument performance limits. As a matter of fact, the current lack of functionally motivated thresholds does not really make sense, since a threshold does exist for alcohol.

Unfortunately, anti-doping researchers show little awareness of the grave consequences of reporting ‘bare’ numbers, i.e. measurement results without a suitable interpretation. What to think of the following quote (source: A. Abbot, ‘What price the Olympian ideal?’, Nature 407 (2000) 124-127): “The antidoping scientists’ job, says Schänzer, “is to say whether or not certain substances are in the body, not how they might have come to get there”.” Perhaps a too leisurely look?

By contrast, a (good!) forensic scientist perceives his responsibility as much broader (source: I. Evett et al., ‘The impact of the principles of evidence interpretation on the structure and content of statements’, Science & Justice 40 (2000) 233-239): “A successful forensic science operation depends on a wide range of technical procedures and skills that will lead, in any individual case, to a set of observations. The crucial element that the scientist brings to any case is the interpretation of those observations. This is the heart of forensic science: it is where the scientist adds value to the process. Any technology-based organisation can set itself up to carry out the purely technical aspects of a forensic examination. The position of a successful forensic science organisation in a Criminal Justice (CJ) system should be characterised by the quality of the scientific inference that it offers over and above the purely technical procedures.” How aptly formulated by Ian Evett: “the scientist adds value” in the form of “interpretation of those observations”.

In the Netherlands, the petition sponsor’s home country, not having these thresholds has led to more than 50% of the convictions in 2008 being questionable.

Please note that this is a call for a sensible decision criterion, not for liberalization of doping.

Finally, it is reiterated for completeness that thresholds are generally not indicated for the category of substances that are forbidden at all times, i.e. in-competition as well as out-of-competition (e.g. exogenous anabolic steroids). It stands to reason that the athlete is liable in that case, regardless the amount of substance detected.


Fragment of the 2009 World Anti-Doping Code, pp. 32-33:

4.3 Criteria for Including Substances and Methods on the Prohibited List

WADA shall consider the following criteria in deciding whether to include a substance or method on the Prohibited List.

4.3.1 A substance or method shall be considered for inclusion on the Prohibited List if WADA determines that the substance or method meets any two of the following three criteria: Medical or other scientific evidence, pharmacological effect or experience that the substance or method, alone or in combination with other substances or methods, has the potential to enhance or enhances sport performance; Medical or other scientific evidence, pharmacological effect or experience that the Use of the substance or method represents an actual or potential health risk to the Athlete; WADA's determination that the Use of the substance or method violates the spirit of sport described in the Introduction to the Code.


Klaas Faber Chemometry Consultancy http://www.chemometry.com/Profile.html Klaas Faber obtained his Ph.D. in chemometrics from the Radboud University (Nijmegen, NL). Between 1994 and 1996, he worked as a post-doc with Bruce Kowalski at the University of Washington (Seattle, USA), and Dave Duewer at the National Institute of Standards and Technology (Gaithersburg, USA). Between 1996 and 2002, he worked as a statistician at the Netherlands Forensic Institute (Rijswijk, NL) and the Agrotechnology & Food Sciences Group (Wageningen, NL). From 2002 onwards, he has led a consultancy company in chemometrics. He maintains active collaborations with academic research groups and has published nearly 100 scientific papers. Michael G. Burke Rice University http://michaelgburke.blogs.rice.edu/ Michael G. Burke obtained his Ph.D. in computer science from New York University. From 1983 to 2009, he worked as a research scientist and manager at the IBM Thomas J. Watson Research Center in New York, in their Software Technology Department. From 2009 on, he has been a senior research scientist at Rice University, in their Computer Science Department. He is an Association of Computing Machinery (ACM) Distinguished Scientist and a recipient of the ACM SIGPLAN Distinguished Service Award. He has published more than 40 computer science journal and conference papers and has authored nearly 20 patents.


The 2009 World Anti-Doping Code:



The 2009 Prohibited List:



International Tennis Federation Independent Anti-Doping Tribunal decision in the Case of Ms. Martina Hingis:



International Tennis Federation Independent Anti-Doping Tribunal decision in the Case of M. Richard Gasquet:



Aaress Lawless, On The Baseline Tennis News, December 14, 2009



Jon Wertheim, Sports Illustrated, September 30, 2009


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