In an address to about 150 people at the University of Otago's 2011 Psycolloquy symposium yesterday, she explored several myths associated with offending, remarking that the area of law and order was one where lay people felt more qualified to influence public policy than professionals.
She likened it to a person who happened to have had flu last year planning health services.
Among programmes that might be "not bad things to be doing" but which did not affect reoffending rates were drama, equine and horticultural therapies, she said.
However, it was a myth to suggest offender rehabilitation was a failed experiment.
What worked were cognitive behavioural interventions aimed at changeable risk factors for crime, and designed for the particular offenders.
Programmes that would work for the "worried well" were not what was required. Programmes also had to be "implemented with integrity".
Prof Polaschek also took issue with the belief, widely held by clinicians and lay people, that psychopaths could not be treated.
There was also the belief treatment actually made psychopaths worse and it would help offenders to read people and further their ability to manipulate them for their own ends.
Prof Polaschek questioned the sense of that. If it were true, why did such people still get caught for violent offences, when it would have been expected they would have learned how not to be caught, she asked.
The audience was told of her research involving high-risk violent offenders at the 30-bed Rimutaka Violence Prevention Unit.
The programme, delivered to closed groups of 10 men, each with about 40 previous convictions, is led by two therapists.
The material covered included examining criminal attitudes, mood management, self-regulation skills, problem solving, communication and relationship skills, and relapse prevention.
The research compared 112 prisoners who completed the programme with 112 similar untreated men.
It showed the violence reconvictions after several years for those who completed the programme was between 10% and 12% lower than those who were untreated.
Men who completed the programme were also less likely to be convicted for any offence.
During questioning Prof Polaschek said the more times people undertook the programme, the more likely it was to be successful.
Offenders had taken a lifetime "becoming the mess they are today" and were not always ready to implement what they had learnt straight away.
Also, much depended on when the programme was run. If offenders still had a year to 18 months in prison after completing the programme, they were not able to put what they had learnt into practice.
Prof Polaschek has emphasised the need for more research into the area if countries such as New Zealand, which has the third-highest imprisonment rate in the West, are not "simply to warehouse even more offenders".