Ms Righarts, who will graduate from the University of Otago today with a PhD in psychology, has developed a method of preparing child witnesses to cope with the rigours of cross-examination.
It involves showing children a video unrelated to the court case and asking them complicated questions about its content, then reinforcing to them that it is acceptable to say if they do not understand a question, and acceptable to say they do not know the answer to a question.
Research had shown children have a natural inclination to please adults, and would rather guess what answer was expected of them than say they either did not understand a question or did not know the answer.
That could have huge implications in court cases, particularly in sex abuse cases where children were the primary witnesses, Ms Righarts said.
The New Zealand Police had "very strict"protocols on how to question child witnesses and prosecutors were given training, but defence lawyers had no such training.
"There are no rules and regulations on how long child witnesses can be questioned for, and no rules about how old children have to be to give evidence. Children of 5 and 6 give evidence in New Zealand courts. In the US, some are as young as 3."
Ms Righarts spent three years testing and refining the preparation programme using more than 360 children from schools in Balclutha, Milton, Kaitangata and Clutha Valley.
The results indicated children who gained confidence about how to answer complicated or confusing questions went on to give more accurate answers in formal interviews.
While there was "lots more to research to do about children's evidence", Ms Righarts said it was exciting to see her research might make a difference.
Raised in Mosgiel and educated at The Taieri High School, Ms Righarts completed a Bachelor of Arts degree with first class honours in Psychology in 2000 and a Bachelor of Laws degree in 2001 at the University of Otago.
She works for the New Zealand Police prosecutions department and was given a part-time position in Dunedin so she could complete her research.
She said she first became interested in children's evidence during her fourth-year psychology studies when the class studied high-profile child sex abuse cases from the 1980s and 1990s such as the Kelly Michaels case (a US child-care worker accused of widespread abuse), the McMartin Preschool in the US (where several child-care workers were accused of abusing children) and the case of Peter Ellis, the Christchurch child-care worker accused and convicted of sexual abuse.
The statements made by the children involved in all three cases were surprisingly similar, and questions were raised about whether their evidence was reliable or might have been prompted by parents or interviewers.
Those cases had led to changes worldwide in the way children were interviewed and questioned in court, Ms Righarts said.
