Susan O'Brien QC has said those giving evidence must have experienced abuse no later than 17 December 2014.
Furthermore, the QC wants any group which wants to express how the inquiry should proceed to make their views known by 31 January next year.
Survivors' groups have previously criticised a lack of progress in the work of the Scottish inquiry.
The probe - established in October after its initial announcement in December, 2014 - will cover abuse within living memory up to 17 December, 2014.
It will examine abuse of children in care and the effects of abuse on children and their families.
The inquiry will also examine the extent of failures of bodies with legal responsibility to protect children in care, whether such failures have been addressed, and if further changes are needed.
Ms O'Brien said: "We are developing procedures to take the evidence of survivors, as it is likely that many individuals will apply to give us their testimony.
"We are considering how best to assess the evidence from victims/survivors and all the other evidence the inquiry receives. We also require to determine which of the witnesses will remain anonymous."
The inquiry will have statutory powers to compel witnesses to give evidence.
It will also examine any instance where a child was abused at institutions including residential care provided by faith-based organisations, children's homes, secure care and those placed in foster care.

The Supreme Court case related to federal law limiting gun ownership for people convicted of domestic violence.
Justice Thomas has said in the past he prefers not to "badger" lawyers as they present their arguments in court.
He spoke weeks after the death of one of the most conservative Supreme Court members, Justice Antonin Scalia, which may shift the court's balance of power.
Justice Thomas on Monday asked a lawyer for the Department of Justice whether the violation of any law "suspends a [person's] constitutional rights".
The court is considering placing new limits on the reach of the federal law banning people convicted of domestic violence from owning guns.
It was the court's second week of oral arguments - when justices are given the chance to question lawyers about their briefs - since the death of Justice Scalia, a friend and fellow conservative of Justice Thomas.
The last time he was reported to have asked a question at the high court was during a death penalty case in February 2006.
Explaining his silence over the years, Justice Thomas told the Associated Press in 2013: "We have a lifetime to go back in chambers and to argue with each other."
He told a group of students in 2000 that "there's no reason to add to the volume. I also believe strongly, unless I want an answer, I don't ask things... Usually, if you wait long enough, someone will ask your question".

Sir Neville started his musical career with the London Symphony Orchestra.
He later established the Academy of St Martin in the Fields, one of the world's leading chamber orchestras.
Its chairman, Paul Aylieff, said Sir Neville's artistic and recording legacy with orchestras and audiences worldwide was "immense".
"He will be greatly missed by all who knew and worked with him and the academy will ensure it continues to be an excellent and fitting testament to Sir Neville," Mr Aylieff added.
A statement from the academy said its founder had passed away peacefully in the early hours of Sunday.
Born in Lincoln in 1924, Sir Neville studied at the Royal College of Music and the Paris Conservatoire.
He first played in a string quartet, then in the London Symphony Orchestra, during which time he decided to form a chamber ensemble from London's finest players.
A group of friends began rehearsing in Sir Neville's front room, before taking their name from the London church of St Martin in the Fields where they staged their first performance in 1959.
The academy, which Sir Neville became life president of, says it now has one of the largest collections of recordings of any chamber orchestra in the world.
Sir Neville has been widely honoured for his work which includes recording the soundtrack for the 1984 film, Amadeus, and becoming the oldest conductor to lead at the Proms, in 2014 at the age of 90.
In March, he was made a Companion of Honour by the Duke of Cambridge at Buckingham Palace, and has also been honoured in France, Germany and Sweden.
The chairwoman of the inquiry into historical child abuse has announced two key dates for the investigation.
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Justice Clarence Thomas, one of eight judges at the highest court in the US, has broken a 10-year silence at court.
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The British conductor and violinist, Sir Neville Marriner, has died at the age of 92, the Academy of St Martin in the Fields says.