During the final days of the Summer Games, countries tally gold medals and total medals and proclaim success or failure. But there is one number that defies easy interpretation: as of Saturday, there had been only six announced positive tests for performance-enhancing drugs, far fewer than the 30 to 40 that International Olympic Committee President Jacques Rogge predicted before the Games from among the 10,500 athletes here.
Some testing officials say the relatively few positive tests -- given the significant advances in drug-testing technology and approaches in recent years -- suggest drug use is being deterred.
Critics argue the exact opposite, that the numbers intimate more cheaters are skirting through loopholes in the testing system.
Drug tests are supposed to have a dual purpose: to sweep performance-enhancing drug users off the playing field and prove that those who pass the tests are drug free. But even 40 years after drug testing became an integral component of Olympic competition and in an era of heightened vigilance and sophistication in drug-testing operations, it remains impossible to say whether either goal has been met during these 16-day Games -- a fact that provides endless frustration for athletes and officials.
"The big issue with results is: Are we seeing less positives because doping is cleaned up, or because athletes have gotten smarter and moved on to other drugs?'" said Don Catlin, chief executive of the U.S. Anti-Doping Research Institute and member of the IOC's medical commission. "We have no way of knowing that. Depending on which side of the fence you sit, you can spin that to your own purpose."
Catlin and other anti-doping officials say they have made steady progress in bringing competence and confidence to drug-testing efforts over the last five years, pointing to enhanced testing methods, more targeted testing and increasing cooperation with law enforcement agencies willing to share hard evidence of drug use among athletes. The IOC has also vowed to save urine and blood samples for eight years to provide an opportunity to reexamine them as better tests are discovered.
Even so, officials acknowledge their bottom-line problem: They can completely miss a cheater. That fact was underscored last fall when American track star Marion Jones, now serving a six-month jail sentence for lying to federal authorities about her drug use, admitted she took steroids during the 2000 Summer Games in Sydney. She won five medals there, but never flunked a drug test.
"When you see athletes doing extraordinary things, you always sit back and say, 'Gee whiz, that guy or girl must be doped,' " Catlin said. "But we don't know. You go all the way back to Sydney, and that was Marion Jones.
"There's no doubt that the good guys are moving forward. The question is, are the bad guys matching the forward move? I don't know how to assess that at this point."
By the end of the Beijing Olympics, the IOC will have conducted about 4,500 tests. That's about 25 percent more than were performed in Athens in 2004, which resulted in 26 positive tests. Besides running the standard battery of tests for steroids and erythropoietin (EPO), officials say, athletes also have been subjected to human growth hormone tests (about 500 to 1,000 will have been performed by the end of the Games). But to date, the HGH test, which was also used at the 2006 Winter Olympics in Turin, Italy, and Athens four years ago, has not produced a single positive.
That fact brings about the usual conundrum for anti-doping officials: Either no athletes are using HGH around the time of Olympic competition, or the test isn't very good.
The inability to guarantee that cheaters are expelled from the Games and winners are clean inevitably leaves a handful of outstanding performers swamped by suspicion and lacking the means to defeat it. There is no greater example at these Olympics than Jamaican star Usain Bolt, who became the first athlete in history to set world records in the 100 and 200 meters during one Olympics. Bolt, who added a third world record and gold medal in Friday's 4x100 relay, has never flunked a drug test, yet his performances have been so otherworldly, Jamaican officials have been hounded with questions about the possibility of performance-enhancing drug use.
"I couldn't care less about the rumors anymore," said Herb Elliott, the Jamaican team doctor. "We have been tested and tested and tested and tested. We know in Jamaica, they have no means of getting at these things. We have very stringent laws in Jamaica."
Hours before Bolt broke his second world record Wednesday, a spokesman for track's international governing body (IAAF) carried a notebook of drug-testing statistics on Bolt to a news conference in which Bolt wasn't even a participant, prepared to publicize Bolt's drug-testing history in the hope of staving off the inevitable doubts.
"Some of our athletes perform extremely well and their performance is put into question," said Juan Manuel Alonso, the chairman of the IAAF's medical and anti-doping commission. "Other sports get more privileges, even though the IAAF has done more to test than other federations."
Some officials complain that Bolt's domination of his sport's glamour events has been met with more cynicism than levied on U.S. swimmer Michael Phelps, whose showing during these Summer Games was at least as incredible. Phelps set seven world records and won eight gold medals last week.
But unlike in swimming, which hasn't seen a major international doping scandal in more than a decade, track and field has seen Olympic medals and world records stripped from a handful of prominent athletes because of doping violations over the last five years. More than a dozen athletes have been suspended since 2004 and two of the four previous 100-meter world record holders lost their marks because of drug suspensions.
"I am ashamed, quite frankly, of my generation and what we did," said Ato Boldon, a four-time Olympic medal winner in 1996 and 2000. "We left the sport kind of tattered. The queen of swimming has never gone down. The king of swimming has never gone down."
Not only has testing failed to catch some of the sport's most notorious cheaters, but there are also widely differing ranges of anti-doping vigilance in different parts of the world. Countries such as the United States, Germany, Australia and New Zealand have their own national anti-doping agencies. But other powerhouse sports nations, such as Kenya and Jamaica, have less stringent steroid laws or lack national anti-doping agencies altogether.
"The fact that an athlete has passed a drug test at the Olympic Games is almost meaningless," Victor Conte, who was jailed for masterminding the drug scheme that led to Jones's incarceration, said in an e-mail. "It makes far more sense to spend a good portion of the available funds for drug testing during the offseason when the athletes are actually using drugs. There are not many athletes dumb enough to show up at the Olympic Games with drugs in their system."
The IAAF has been trying to address that problem, IAAF President Lamine Diack said, spending between $2 million and $3 million annually on its own drug testing and focusing on nations that don't have their own national anti-doping agencies. There are 22 elite Jamaican athletes, including Bolt, who have been "targeted" for regular testing, IAAF spokesman Nick Davies said. All have undergone urine testing, blood testing and blood profiling -- an accumulation of testing information designed to signal irregularities even when tests are not actually positive.
About a week before the Games, the IAAF announced it had banned seven Russian athletes after a year-long investigation showed they were providing urine samples that weren't their own to testers. The IOC, meantime, has broadened its pre-Olympic testing, tracking down athletes for urine and blood tests much earlier than in the past in an attempt to catch them off guard. One casualty of that extra testing, Catlin said, was Greek hurdler Fani Halkia, the gold medal winner at the Athens Olympics. She was caught using methyltrienolone and banned before she competed.
"We're using much more intelligent testing and targeted testing," said Arne Ljungqvist, the chairman of the IOC's medical commission. "I feel the sport is becoming more clean and people probably understand that doping is not the way to go."
Ljungqvist's point might be arguable, but there is one issue about which there is no debate.
"Doping will never be something entirely of the past," Diack said. "We will always have people who cheat."