The depraved BBC presenter, who received a knighthood in 1990, died in 2011 and so never faced justice for his crimes.
A report into how Jimmy Savile and Stuart Hall carried out decades of abuse while at the BBC is to be published in May.
Dame Janet Smith said her review had contacted 775 people and had now finished taking evidence.
It interviewed 375 witnesses as part of the Savile inquiry, and more than 100 in the Hall investigation.
Dame Janet said she is "discussing a timeline for delivery and arrangements for publication of the report with the BBC," but expects it to be released "in the second half of May".
The report is expected to uncover hundreds of victims and reveal a BBC culture of ignorance which protected Savile.
Another report, published last month, said NHS hospitals had still not fully learned the lessons of the Savile scandal.
It said he was given "endorsement from the very highest level of society" after then-prime minister Margaret Thatcher gave him an official fundraising role at Stoke Mandeville Hospital.
Savile raped or assaulted at least 63 patients, staff and visitors at the hospital. Some of them were desperately ill children.
Barrister Kate Lampard said the access he was given by the NHS offered him the "opportunity to commit sexual abuses on a grand scale for nearly 50 years".
Last year Hall, who hosted BBC show It's A Knockout, was jailed for two-and-a-half years for indecently assaulting a girl under the age of 16.
He was already serving a 30-month jail term after he pleaded guilty in 2013 to indecently assaulting 13 other young girls, aged between nine and 17, over a 20-year period.