There is a lot of public discussion about the criminal justice system, which is likely to continue as the government is encouraging that discussion with a view to a package of reforms.

Last month, Justice Minister Andrew Little announced an advisory group to look at changes to New Zealand’s criminal justice system, and a Criminal Justice Summit, to be held from 20 to 22 August.

Many of us will have experience in different parts of the criminal justice system that inform our perspectives, and potentially little exposure to other parts of the system. The perspective of the police, prosecutor, defence counsel, registry staff, judges and a host of other people (eg, victims advisers, restorative justice providers, probation officers) are all different.

I want to put some system-wide data on the table, and demonstrate what those numbers mean in human terms to help inform the debate about the sort of criminal justice system New Zealanders want.

I’m sure it is no surprise to most that the prison population is about 10,500, and is projected to keep climbing. We already have one of the highest rates per head of population in the OECD.

There are around 100,000 people in New Zealand who have served a prison sentence.

At any one time, there are around 20,000 children in New Zealand who have a parent in prison. Research shows children with a parent in prison suffer from poorer health, poorer results at school, and a host of other negative social outcomes, and are then at higher risk of going to prison themselves.

New Zealand also has a high reoffending rate. About 60% of people are reconvicted within two years of release from prison. Of that number, 42% are back in prison within the two years.

Of the people in prison:

• 37% have diagnosed mental health problems;
• 65% have difficulty with literacy and numeracy;
• 47% have an addiction problem;
• 77% have been victims of violence themselves, particularly women in prison; and
• 46% of people starting a prison sentence have suffered a traumatic brain injury.

At the risk of switching from percentages to fractions, for everyone in New Zealand who was born in 1978, one in four have a criminal conviction. One in three men born that year have a criminal conviction.

The picture is bleaker for Māori and Pacific men. Half of the Māori and Pacific men born in 1978 have a criminal conviction. For most New Zealanders, being arrested, convicted and sentenced is an extraordinary event – for some communities, however, it is sadly, a normal part of life.

And that connection with the criminal justice system doesn’t just stop there. Twenty-four percent of adults were victims of crime, according to research from 2014. But some people are affected more often than others: the same study also found 3% of adults experienced more than 50% of all crime.

I’d urge everyone to think about the kind of criminal justice system New Zealand needs, and I want to encourage you to take part in the events, make submissions, share your perspectives and join the discussions happening in the coming months.