A trial has heard claims that a school in Gwynedd, where a three-year-old pupil suffered a head injury in a fall, had a very good safety record.
The fall happened at Hillgrove School in July 2004
Kian Williams died a month after jumping off steps at Hillgrove School in Bangor, Mold Crown Court has heard.
Head teacher James Porter denies breaching health and safety laws.
His barrister said its accident record was better than schools quoted by experts as having greater supervision of nursery pupils. The case continues.
Patrick Harrington QC, defending, said that one of the 13 schools visited by the Health and Safety Executive (HSE) to see the level of supervision of pre-school-age children had 442 incidents involving infant and junior aged children.
Kian Williams, aged three, had been pretending to be Batman
However, he told the court the number of accidents at Hillgrove, an independent school, for the same period had been four.
The jury has heard Kian, from Bethesda, was pretending to be Batman and was unsupervised in the playground when he was hurt jumping from the brick steps in July 2004. He died in hospital the following month.
The jury heard from Stephen Scott, principal inspector in charge of the HSE investigation, who said that many factors were involved.
He told the jury that, while he had a great respect for a lot of the ethos at Hillgrove, "what I had were very serious concerns about his awareness of the kind of supervision ratios and standards at other schools, and the actual supervision and exposure to hazards for three to four-year-olds".
He added that greater supervision was required for three-year-olds, and that was expected by parents.
Details of interviews held between investigators and headmaster Mr Porter were read out to the jury on Wednesday.
The court heard Mr Porter told police that he believed supervision at his school met the required standards but that there were risks in every situation.
To have a completely risk-free environment would take from the children, particularly the boys, he said.
He told police that boys needed to be able to take risks and they could not remove all risks from play.
Mr Porter said that the steps were safe, well-constructed steps, but if a child decided to throw himself off the steps he would injure himself.
Supervision at his school was "dynamic", he said, and children were told which areas were out of bounds.
He added pupils were supervised by experienced teachers and children were also taught to report other children who strayed.