April 17, 2006

WADA Statistics 2005

A couple of weeks ago WADA released a summary of their anti-doping test results for 2005. The rate of positive tests saw a sharp increase, from 1.03% (19/1848) in 2004, to 1.96% (61/3114) in 2005.

I have written before about the fact that these numbers, as reported, never include error bars — estimates on the uncertainty in the real rate of doping.

As I noted in that post, if we assume that the rate of positive tests is an accurate measurement of the doping rate in the athlete population, it's actually fairly simple to calculate the uncertainty that goes with that measurement. Using that algorithm, the 2004 rate becomes (1.03 ± 0.24)%, and the 2005 rate is (1.96 ± 0.25)%. The increase is almost four standard deviations, so it's clearly significant.

WADA had their own explanation for the increase:

The 2005 figures include several elevated T/E ratios [a urine parameter used in testosterone testing] over 4, which were not reported in previous years when the threshold was 6, partially accounting for the increased number of AAFs [Adverse Analytical Findings] in 2005. However, there is a significant increase in other AAFs, such as those for steroids. One reason for this may be WADA’s increasingly targeted approach to testing.

WADA is suggesting, then, that the increase in the rate of positive tests is not due to an increase in the rate of doping; it's because of an increase in the effectiveness of the testing program. In short, WADA has succeeded in testing more cheaters. We can take that suggestion under consideration; it's difficult to prove the case either way.

I should (again) point out that the measured doping rate is still extremely low. I think it is far below the rate that most people would guess, if you asked them what percentage of elite athletes use performance-enhancing drugs. Although I would have to assume that the measured rate is an underestimate of the actual rate, I think the common wisdom exaggerates the prevalence of doping.

I've come to realize, however, that this is almost like arguing over religion; some people will never be convinced. A lack of positive tests simply proves, for those sports fans, that the testing program is ineffective. It's the old axiom that "absence of evidence is not evidence of absence." And if the positive test rate ever reached zero, it would only prove that testing is 100% ineffective. So to those people, I have to ask: what kind of proof would change your opinion? Perhaps you'd be convinced by around-the-clock surveillance?

Even if an athlete is tested every day, somebody will suggest that we don't know what he's doing in his bathroom after showering and maybe that's when he injects undetectable steroids. … OK, fine, says the athlete. Put a Web cam on me for six months before the Olympics and feed it straight to a small panel of testers at USADA. Then they will know what I'm doing in my bathroom. Better yet, attach a USADA rep to my hip for six months before the Olympics. Let him check the trash every day. Let him frisk my visitors.

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