Key Points:

Kim Workman, a former Assistant Secretary of Justice, says professionals in criminal punishment are becoming increasingly concerned that public policy is being made without evidence-based research, good information or adequate consultation. He said this a day after National's Minister of Police and Corrections, Judith Collins, declared the new Government was determined to overhaul home detention and parole.

In Ms Collins' view, the public has lost faith in sentencing and parole laws and in particular are "rightly concerned ... that sentences of home detention are given to violent criminals". Mr Workman, speaking as director of a non-government "Rethinking Crime and Punishment" project, asserts that the increased use of home detention has not even registered with the public and there is not much concern about it. Who is right?

Probably Mr Workman when he notes the public are not generally aware that home detention is available for violent offenders. But that is no reason to suggest they would be relaxed about it. Mr Workman is right on his wider point too, that criminal justice policy tends to be made for political appearances rather than as a result of research on its need and efficacy.

Some of National's rushed post-election legislation falls into that category, as did many laws advanced by Labour's leader, Phil Goff, when he had charge of penal policy. Politicians respond to public annoyance, whether it is justifiable or not, and often they promote it.

But there is no point in criminologists complaining that their theories and research are being swamped by ignorance, prejudice and political posturing when policy is made. If their research and reasoning are factual and robust, they will be competitive in the political contest.

They need to start by recognising that the public's prime interest is not the human rights and rehabilitation of those who have broken the law, as the professionals seem to think. Those are important but when they are weighed against the interests of due punishment and public safety, there is no contest for most people. The professionals need to convince the public that their ideas better serve the interests of punishment and safety overall.

On the issue of home detention, Mr Workman says 31 per cent of those given the sentence were reconvicted within two years, compared with 57 per cent of those released from prison. And administration of home detention costs the taxpayer $21,000 a year against $76,000 if the offender is in prison.

That is a good cost-benefit argument for home detention but the issues of safety and due punishment remain. It is disturbing to learn that violent offenders can serve their sentences at home. And severely injured victims of dangerous drivers have been outraged recently to see those convicted given home detention. The public has yet to be convinced that confinement with home comforts is a sufficient hardship.

One case in the Tauranga District Court this week can at least inspire confidence in enforcement of the sentence. A Papamoa teenager who cut off his ankle bracelet to go to a New Year's Eve party was told he is likely to go to prison when he reappears on February 25. Despite an anguished appeal from the teenager's mother, Judge Thomas Ingram said, "People who cut off their bracelet go to prison. It is as simple as that".

Criminal justice is seldom simple. Every case is different. Sensible sentencing has to balance the public interests and the offender's prospects of correction. The challenge for professionals is to devise sentences that serve both ends fairly and effectively.