1 Was Armstrong still doping during his Tour de France comeback in 2009 and 2010?
What Lance told Oprah "The only thing that really upset me is the accusation, and the United States Anti-Doping Agency say the proof, that I doped after my comeback. The last time I crossed that line was in 2005. I didn't do any blood doping in 2009 or 2010. Absolutely not."
What Usada said "An expert examination of Armstrong's blood parameters establish the likelihood of his blood values from the 2009 and 2010 Tours de France occurring naturally is less than one in a million, and build a compelling argument consistent with blood doping."
What we still need to know How can he account for the medical findings? Usada and Wada took 38 blood samples from him between Oct 16, 2008, and April 30, 2012, as part of their "blood passport" testing system. Armstrong will be aware of the eight-year statute of limitations under the Wada code. His previous offences fall outside this. The comeback does not, which leaves him facing further legal battles if he admits doping during this period.
2 How widespread and sophisticated was Armstrong's network of doping, and what roles were played by Dr Michele Ferrari, Dr Luis Garcia del Moral and Johan Bruyneel, three men who were charged by US anti-doping officials with him?
What Lance told Oprah "It was definitely professional. It was definitely smart, if you can call it that but it was very conservative, very risk averse?... But to say that the program was bigger than the East German doping program in the 70s and 80s, that's not true."
What Usada said The evidence shows beyond any doubt that the US Postal Service Pro Cycling Team ran the most sophisticated, professionalised and successful doping program that sport has ever seen. The USPS Team conspiracy was professionally designed to groom and pressure athletes to use dangerous drugs, to evade detection, to ensure its secrecy and ultimately gain an unfair competitive advantage through superior doping practices."
What we need to know Armstrong admitted he doped but he did not name other names. He admitted he used the services of 'Motoman', the courier paid to drop off EPO in the 1999 Tour but did not reveal his true identity. He admitted faking a doctor's note to explain away a positive test for cortisone in 1999 but was not asked why the authorities accepted it so readily. Of Ferrari, he only went as far as to describe him as a good man. Armstrong gave nothing away about team managers and backroom staff who helped smuggle drugs transfusions.
3 Did the International Cycling Union help to suppress a positive test by Armstrong for EPO from the 2001 Tour de Suisse in return for a $100,000 donation from him?
What Lance told Oprah "It was not an exchange for any cover-up. I am not a fan of the UCI. I have every incentive to say, 'Yes that was right, they are all crooked'?...?There was no positive test. There was no paying off the lab. There was no secret meeting with the lab director."
What Usada said "Armstrong told Tyler Hamilton and Floyd Landis that he had tested positive for EPO at the 2001 Tour of Switzerland and stated or implied that he had been able to make the EPO test result go away."
What we need to know Armstrong is accusing Hamilton and Landis of lying. Hamilton claims Armstrong told him "his people had been in touch with UCI, they were going to have a meeting and everything was going to be OK". Landis said that Armstrong told him "he and Mr Bruyneel flew to UCI headquarters and made a financial agreement to keep the positive test hidden." Investigators will want Armstrong to explain these comments and his relationship with Hein Verbruggen, the head of the UCI at the time.
4 Did Armstrong confess to doping in a hospital room in 1996, as Betsy Andreu, wife of Armstrong's team-mate Frankie, has testified?
What Lance told Oprah "I'm not going to take that on. I'm laying down on that one."
What Usada said "The hospital room confession is significant for other reasons than proving that Armstrong's doping began more than a decade and a half ago. Mr Armstrong's response to the incident once it was publicly exposed provides insight into his tactics in addressing potential witnesses who dared to come forward with evidence."
What we need to know Why was Armstrong not prepared to address this during what was supposed to be a confession? Could he be protecting his doctor, Craig Nichols, who provided sworn testimony that the confession did not take place? Nichols is now a board member on Livestrong, Armstrong's foundation.