"Then the systems to support that practice just aren't there - quality systems, systems to share good practice. If we can improve those two things and make our system more child-centred, then we'll see improvement."
Mr Wills said New Zealand does not have enough caregivers.
"We do need more staff. We certainly need more caregivers, but equally important, they need to have the right skills.
"Currently, social workers told us that they graduated without the skills that they need. Child, Youth and Family have good training but the workload is such that they can't get to that training.
"And then the supervision; that experienced social worker who can sit down with them and help them to think through a case and make really intelligent decisions, that supervision often wasn't there consistently. When you put all that together, then that's a recipe for inconsistent practice, which is what the kids told us happened."
More investment was needed in both children and the caregivers, he said.
"Caregiving's a tough job. These are very damaged kids, often. But what caregivers told us is when they've got good training and good support, they hang in there. The social workers make good decisions. They wrap supports like child and adolescent mental health services around those caregivers, and when that happens, the kids come right. They heal, and they're transformed, and caregiving can be a wonderful, satisfying thing to do, which is why caregivers keep coming back."
More financial support was needed for caregivers to do their job properly, he said.
"We need to bump up all of those supports - the financial support, but also the skilled, professional support that's there with the caregivers so they can hang in there, use good skills to help those kids to heal, and to get better."
Judge Henwood said the financial aspect was "incredibly important".
"You need the right amount of money to do the job, and I don't know whether money is being used to manage the department, or whether money is being used to put into the children. And that's a hard question. It's not transparent. We do not know how that money's being spent."
There "doesn't seem to be enough money", she said.
"Well, not the right amount of money to deliver what is needed."
Mr Wills said he expected the Government's reform of CYFs would include more money and training.