Director of Public Prosecutions Alison Saunders told ITV News that acquittals - such as those of Dave Lee Travis and Bill Roache - does not mean there were flaws in the prosecution.
She added: "We have to be sure there is a realistic prospect of conviction, a jury has to believe beyond all reasonable doubt the case is proved. That is a very different test, it is a higher test."
Director of Public Prosecutions Alison Saunders has said Operation Yewtree - the police investigation launched in the wake of the Jimmy Savile scandal - has been a success, despite only four individuals being charged.
She told ITV News UK Editor Lucy Manning that the fact the CPS is able to bring cases forward showed the operation is a success.
She added that Operation Yewtree has "enabled us to have a public debate about abuse that has taken place some time ago."
The Director of Public Prosecutions Alison Saunders has said the Jimmy Savile scandal was a "watershed moment" that made the Crown Prosecution Service look at the way it treated victims of historical abuse.
She added that prosecutions that followed in the wake of the Savile scandal "were not a knee-jerk reaction".
The Director of Public Prosecutions, Alison Saunders, has given her first reaction to the acquittals of William Roache and Dave Lee Travis in the face of criticism about the decision to prosecute them.
Alison Saunders told ITV News the cases were not a knee-jerk reaction to the Jimmy Savile scandal and the men were not scapegoats for the failure to prosecute Savile. She denied Operation Yewtree had turned into a celebrity witch-hunt.
Ms Saunders said it has always been difficult in sexual abuse cases to take them before juries but it was right to continue to do so and there had been convictions.
After the criticism that the police and prosecutors have faced, this is a robust defence from the head of the Crown Prosecution Service, who must decide if others like Freddie Starr and Gary Glitter should still be charged.