What are 'whereabouts failures' and how did they cause Penny Oleksiak’s swim ban?

Canadian swimmer Penny Oleksiak's two-year ban from competition has raised questions about the reasons for her suspension: three whereabouts failures.

In its World Anti-Doping Code, the World Anti-Doping Agency (WADA) defines a whereabouts failure as any combination of three missed drug tests or "filing failures" in a 12-month period.

Swimming Canada chief executive officer Suzanne Paulins said in a statement on Tuesday that the organization accepted Olesiak's explanation these "were inadvertent errors and she has not used banned substances."

Oleksiak is tied with sprinter Andre De Grasse as Canada's most decorated Olympian, having won seven medals over her career.

Here's what we know about the whereabouts program, the responsibilities of athletes who are part of the program, and potential violations of the program.

The whereabouts program is part of WADA's drug-testing program that applies to all international Olympic federations and their athletes, and also all national anti-doping organizations and the athletes subject to their rules.

The program requires certain athletes to submit information about their daily routine so they can be located for a random drug test.

An identified group known as the Registered Testing Pool (RTP), a group of elite-level athletes who are generally believed to be at higher risk for doping and should be subjected to more testing.

Along with the very top athletes, the pool can include those coming off an injury, or those who have returned to competition after previously retiring. It can also include athletes whose performance has suddenly peaked.

Every sport in every country has its own criteria for determining who should be in the RTP, according to Janie Soublière, a lawyer who specializes