So it looks like 70% of 2011 IAAF World Champ competitors would not admit they doped, even to an anonymous survey

A process of indirect questioning was used for the study titled "Doping in Two Elite Athletics Competitions Assessed by Randomized-Response Surveys" in order to guard the athletes' anonymity.

More than 90 percent of athletes asked to take part agreed to do so.

Only 0.5 percent of drugs tests in Daegu were positive, while the figure was 3.6 percent at the Pan-Arab Games.

"The study shows that biological tests of blood and urine reveal only a fraction of doping cases," said Harrison Pope, Harvard Medical School professor.

"As described in the publication this is likely due to the fact that athletes have found numerous ways so as not to be caught during tests."

The study's release had been delayed for years as the researchers wrangled with the World Anti-Doping Agency (WADA) and the international association of athletics federations (IAAF) over how it was to be published, researchers said.

It has now been published in Sports Medicine magazine.

Background

Doping in sports compromises fair play and endangers health. To deter doping among elite athletes, the World Anti-Doping Agency (WADA) oversees testing of several hundred thousand athletic blood and urine samples annually, of which 1–2% test positive. Measures using the Athlete Biological Passport suggest a higher mean prevalence of about 14% positive tests. Biological testing, however, likely fails to detect many cutting-edge doping techniques, and thus the true prevalence of doping remains unknown.

Methods

We surveyed 2167 athletes at two sporting events: the 13th International Association of Athletics Federations Word Championships in Athletics (WCA) in Daegu, South Korea in August 2011 and the 12th Quadrennial Pan-Arab Games (PAG) in Doha, Qatar in December 2011. To estimate the prevalence of doping, we utilized a “randomized response technique,” which guarantees anonymity for individuals when answering a sensitive question. We also administered a control question at PAG assessing past-year use of supplements.

Results

The estimated prevalence of past-year doping was 43.6% (95% confidence interval 39.4–47.9) at WCA and 57.1% (52.4–61.8) at PAG. The estimated prevalence of past-year supplement use at PAG was 70.1% (65.6–74.7%). Sensitivity analyses, assessing the robustness of these estimates under numerous hypothetical scenarios of intentional or unintentional noncompliance by respondents, suggested that we were unlikely to have overestimated the true prevalence of doping.

Conclusions

Doping appears remarkably widespread among elite athletes, and remains largely unchecked despite current biological testing. The survey technique presented here will allow future investigators to generate continued reference estimates of the prevalence of doping.