Criminal Justice Policy The background evidence

This paper covers evidence supporting The Opportunities Party’s criminal justice policies. In some cases it covers the same evidence referred to in the long Description of these policies, but in more detail or with more discussion. 

Recorded crime rate that has been falling since early 1990s…1.jpg

This fall in recorded crime was not unique to New Zealand. New Zealand was part of a trend observed in most of the western world (Tonry. 2014).

…including violent crime


Source: Statistics NZ: Annual Recorded Offences for the latest Calendar Years (ANZSOC) 1994 to 2014, Recorded (not Resolved) at


Because a homicide is unlikely to be missed, homicide statistics probably accuratly track actual homicides. 

A recent small upswing in recorded violent crime is due to an increase in violent crime in dwellings and may reflect more reporting rather than more actual crime



The graph ‘Number of violent crimes’ at

The lines are to be read as each indicating independent values that if added together give the total recorded violent crime.

New Zealand’s prison population is large by comparison with historical and international norms

Prison population, March 2017

















Prison Facts and Statistics – March 2017, Department of Corrections

New Zealand prison population rate (prisoners per 100,000 of the general population) - 1950-2016


The remand prison population has grown sharply since 2013 

The Bail Amendment Act 2013 had a dramatic effect on the remand prison population (those in custody awaiting trial or sentencing). Bail became significantly more difficult to get. 


Source: Department of Corrections: Prison Statistics (, December of each year)

Although there are comparable countries with high remand populations as a portion of total prison populations, New Zealand’s is high. Also, among the selected jurisdictions below, except for the United States, New Zealand has the largest remand population as a portion of the general population.

Pre-trial/remand populations as percentage of total prison population and per 100,000 of general population: selected jurisdictions - 2016


 New Zealand compares poorly with other advance economies for the share of our population we put in prison


Reducing New Zealand’s prison population is a realistic goal

The goal of reducing New Zealand’s prison population to 6000 by 2027 would return us to a historical and international normal. If Australia, the United Kingdom, Canada and Ireland have smaller prison populations for the size of their populations, why not New Zealand?

Other countries have also reduced their prison population. Finland’s prison population (prisoners per 100,000 of the general population) at the beginning of the 1950s was 200, which makes it comparable to New Zealand now, about 210. In the 1970s, Finland’s prisoner rate continued to be among the highest in Western Europe. It is now 57.

However, political will is needed. This observation was made on the successful Finnish experience of reducing prison numbers (Törnudd. 1993, quoted in MoJ. 1998 at 105):

The decisive factor in Finland was the attitudinal readiness of the civil servants, the judiciary and the prison authorities to use all available means in order to bring down the number of prisoners.... it is that attitudinal and ideological readiness to bring down the number of prisoners [which] is more important than the choice of technique to achieve this end.

Prison is expensive



Compared with other sentences, prison is expensive


Department of Corrections, Annual Report 2015/16, ‘Offender Summary’ (


We spend a disproportionate amount on locking people up rather than rehabilitating or reintegrating them

Departments of Corrections Expenditure


Department of Corrections Annual Report 2015/16, ‘Financial Review’ (


Offenders and victims of crime are unevenly distributed

Everywhere you look, the New Zealand criminal justice landscape is lumpy. For this reason, totals and averages should often be treated with some caution since they are probably a bad guide to anyone’s experience of crime.

The Dunedin Study[i] which follows the lives of a cohort of 1,037 people born in Dunedin, New Zealand, in 1972/73, found that over the 38 years after their birth, 20% of the cohort accounted for 97% of total criminal convictions within the cohort (Caspi, Houts, Belsky et al. 2016 at 2).

Prisoners are disproportionately Maori (15% of the general population; 51% of the prison population) and men (96% of the prison population[ii]).


Department of Corrections, Prison facts and statistics – December 2016 (


Department of Corrections, Prison facts and statistics – December 2016 (

The Opportunities Party expects that iwi will be an important part of the solution to New Zealand’s high rate of imprisonment because of the high number of Māori in the criminal justice system, and because the different perspective iwi bring - tikanga Māori - could make the whole system more innovative. 


It is notable that if Māori were put in prison in proportion to their share of the general population (i.e., if they were 15% of the prison population) then the current prison population would be 6,500.[i]

It might be worth investing in Māori prisons. Canada provides a model of indigenous prisons that could be studied.  Canada is like New Zealand in that it has a history of colonialisation and the incarceration rate for Aboriginal adults in Canada is much higher than for the general population. It is estimated to be 10 times higher (Office of the Correctional Investigator. N.d).

In the Canadian model the primary role of the indigenous prison is to integrate the offender back into the community.

Aboriginal Canadian prison inmates can request to go to the Stan Daniels Healing Centre (Edmonton Alberta) to serve the last 6 months of their sentence. (Women offenders can request to go to the Buffalo Sage Wellness House.) Residents at the Centre are either conditionally released offenders or serving a custodial sentence.

The Centre is run by the Native Counselling Services of Alberta (NCSA), which provides the Centre and other theraputic and educational programs. (The range services is listed at: NCSA was established in 1970 with the objective of providing Courtworker assistance to Aboriginal people in conflict with the law, and has grown since then. “NCSA programs and services are designed and delivered for Aboriginal people, by Aboriginal people.”[ii]

The legislation supporting transfering prisoners to the Centre is sections 81 and 84 of the Corrections and Conditional Release Act (CCRA. 1992). Section 81 provides for the governemnt to contract with ‘an aboriginal community’ for ‘correctional services’, and that the government can transfer an offender to ‘the care and custody’ of an aboriginal community with the consent of the offender and the community. Section 84 provides for an offender to initiate a process that might result in them being transferred to the care of an aboriginal community.

Correctional Service Canada (CSC, equivalent to our Department of Corrections) describes the rationale behind sections 81 and 86 as (CSC. Nd.):

The successful reintegration of offenders into society depends upon a strong and effective community focus. It is in the interests of the community itself that it be involved in the corrections and reintegration process for offenders who will be living in the community. Aboriginal communities know best how to use their values, strengths, and relationships to assist offenders in reintegration. If a community-based, restorative model of justice is preferred, that cannot be imposed by CSC, it must originate in the community itself. 

After ethnicity, gender is the most noticeable disparity in the prison population

Department of Corrections, Prison facts and statistics – December 2016 at

Within the category of men, young men aged 20 to 29 make up more than 30% of the prison population, more than any other decade age band. 


Victimization is also uneven. The survey evidence we have suggests that a small group, in 2013, 3% of the adult population, experience over half, 53%, of all crime; that Māori are more likely than non- Māori to experience all types of crime; and that people experiencing financial hardship or living in more highly deprived areas are more likely to be the victim of crime than other New Zealanders (NZCASS. 2008; NZCASS. 2013).

People convicted or imprisoned are often worse off than the average New Zealander

Evidence from the Dunedin Study suggests that the group of New Zealanders with criminal convictions includes a large share of unusually disadvantaged New Zealanders.  Data from the Dunedin Study was used to select for individuals in the Study’s cohort associated with various kinds of high-costs: injury claims, excess weight, smoking, hospital stays, social welfare and criminal convictions (Caspi, Houts, Belsky et al. 2016). It turns out that 22% of the individuals in the cohort belonged to all these high-cost groups, while 30% have an unusually low-cost footprint. From the point of view of this paper, it is significant that those in the high-cost group accounted for 81% of criminal convictions in the cohort, with the low-cost footprint accounted for 0% of criminal convictions.


Caspi, Houts, Belsky et al. 2016. ‘Childhood forecasting of a small segment of the population with large economic burdens’. Nature Human Behaviour. Figure 4 on p 7.


Caspi, Houts, Belsky et al. 2016. ‘Childhood forecasting of a small segment of the population with large economic burdens’. Nature Human Behaviour. Figure 4 on p 7.

Prisoners are a subset of offenders convicted of more serious offences or are repeat offenders who have worked work up the scale: a fine, then community work, then community detention, then home detention then prison. The subset of offenders in prison has been intensely studied. We know that on the whole they significantly worse off than the average New Zealander. 

The following table and three graphs comparing the general population to the prison population are from a study over 1,200 prisoners in 13 New Zealand prisons in 2015 (Indig, Gear and Wilhelm. 2016). The general conclusion was that (Indig, Gear and Wilhelm. 2016 at vii), “prisoners had high rates of mental health and substance use disorders including high rates of comorbidity which were often undetected and under-treated.”


Indig, Devon, Craig Gear and Kay Wilhelm (June 2016) Comorbid substance use disorders and mental health disorders among New Zealand prisoners. Department of Corrections, at p. 24, Table 4.1.


Indig, Devon, Craig Gear and Kay Wilhelm (June 2016) Comorbid substance use disorders and mental health disorders among New Zealand prisoners. Department of Corrections 


Indig, Devon, Craig Gear and Kay Wilhelm (June 2016) Comorbid substance use disorders and mental health disorders among New Zealand prisoners. Department of Corrections.


Indig, Devon, Craig Gear and Kay Wilhelm (June 2016) Comorbid substance use disorders and mental health disorders among New Zealand prisoners. Department of Corrections.

The main drivers of crime are social and economic

Criminal justice outcomes are largely determined by what happens in society, not in the criminal justice system.


One of the most ubiquitous research findings has been a consistent link between socio-economic deprivation or disadvantage and elevated rates of crime. These findings have been replicated for many societies and using different measures of socio-economic disadvantage (references cited in Fergusson and Swain. 2004). There can be no doubt that individuals from socio-economically deprived environments show a greater propensity to commit crimes.


This was confirmed by evidence from the Christchurch Health and Development Study, a longitudinal study of 1,265 children born in Christchurch in 1977. As expected, for the Study’s cohort from birth to 21 years of age, socio-economic deprivation was positively correlated with increased rates of self-reported crime and officially recorded criminal convictions (Fergusson and Swain. 2004). Looking at the data more closely, it was found that it was the positive association between socio-economic deprivation and family adversity (physical punishment, child abuse, low attachments to parents etc.), early behavioral problems, school problems and deviant peer affiliations (family adversity had the greatest effect) that explained the link between socio-economic deprivation and more criminal activity. Without family adversity and the other disadvantages, the link between socio-economic deprivation and crime was not statistically significant.     


In addition, there appears to be a relationship between the prison population rate of a country (the number of people in prison per 100,000 of the general population) and economic inequality in that country: the more inequality the higher proportion of its citizens a country tends to puts in prison (Wilkinson and Pickett. 2010, chapter 11).[i] The same relationship between inequality and prison populations in countries is also found in individual US states. The more unequal states tend to imprison a higher share of their population (Wilkinson and Pickett. 2010 at 149).


The longer term historical evidence supports the view that society rather than criminal justice policy are the main determinates of criminal justice outcomes. There is evidence the that crime rates have moved in parallel in Western societies since the late Middle Ages (Tonry. 2014). The long-term trend has been declining crime. (Tonry. 2014 at 1) notes that “Diverse explanations have been offered for both the long- and short-term declines. [The post WWII increase in crime is a historical anomily: crime rates in major western cities and countries declined from the early nineteenth century until the middle of the twentieth.] Most agree that, whatever the explanations may be, they do not include direct effects of changes in policing or sanctioning policies.” The long terms trends seem to be relatively unafected by different criminal justice policies across western countries and in the same country over time.


Prisons probably cause crime

“Most criminologists would predict that, on balance, offenders become more,

rather than less, criminally oriented due to their prison experience.”

US criminologists, Francis T Cullen, Cheryl Leo Jonson and Daniel S Nagin (Cullen, Jonson and Nagin. 2011 at 53S) 

Those with the most direct experience of prisons, ex-prisoners, often reoffend. Of the prisoners released in New Zealand in 2014/15, within 12 months, 29.7% were re-imprisoned and 44.2% were reconvicted (Corrections. 2016). (Re-imprisonment is associated with more serious offences or with the same person repeating less serious offences that the courts respond to with increasingly punitive sanctions: fines, then community work, up the scale to prison.)

A 5-year follow up study on a sample of almost 5,000 prisoners released from New Zealand prisons in 2002/03 found at the 12-month mark that 28% were re-imprisoned – close to the 2014/15 figure, so no reason to think things have changed since 2003. At the 5-year mark, just over half, 52%, had been re-imprisoned, and over two thirds, 71%, had been reconvicted (Nadesu. 2009. For the re-imprisonment rate see Graph 1; the re-conviction rate, Graph 2). As not all crimes are detected and punished, and there is a natural tendency for people to do less crime as they age,[ii] the actual failure of prisons to deter or rehabilitate could be close to 100%.


Nadesu, Arul (March 2009) Reconviction patterns of released prisoners: A 60-months follow-up analysis, Graph 1, p. 6. ( 


Nadesu, Arul (March 2009) Reconviction patterns of released prisoners: A 60-months follow-up analysis, Graph 2, p. 7. ( 

There are credible mechanisms that might explain why so many prisoners reoffend. First, prisons are ‘schools for crime’ and ideal places to recruit for criminal enterprises. Second, having been in prison, ex-prisoners suffer stigmatization which makes it harder for them to find employment and reintegrate into society. Third, many prisoners have problems– substance abuse, mental disorders, low literacy, so forth – that are connected to the choices they have made and which prison either fails to adequately address or makes worse.

It is possible that while prison does not reduce the likelihood that offenders will reoffend after being released from prison, prison nonetheless deters others in society from offending, and in this way it reduces crime. If discovering what affect the prospect of prison has on prisoners is hard, figuring out what affect it has on others in society, is much harder. However, one way to test an idea is apply it and see if it works. If it works then the idea passes the test and becomes more credible. 

‘Scared Straight’ is a program based on the appealing idea that by making the punitive prison experience more vivid to juveniles and children they will be less likely to offend. It involves organized visits to prison for juveniles and children at risk of becoming delinquent. A systematic study of the available research found that not only do Scared Straight programs fail to deter crime, they cause more offending behavior (Petroino, Tupin-Petrosino, Hollis-Peel and Lavenberg. 2013). The idea fails the test.

In some places prisons do not cause crime. There is good evidence that prisons in Norway reduce the likelihood of reoffending (Bhuller, Dahl, Løken and Mogstad 2016). Measured against a baseline of similar offenders not sent to prison, prison time in Norway lowers the probability an individual will reoffend within 5 years by 27%. The baseline is constructed by exploiting the random assignment of criminal cases to judges who differ systematically in their stringency in sentencing defendants to prison. However, that result is explained by a particular cohort of Norwegian prisoners. The decrease is due to prison’s affect on the cohort of individuals not working prior to prison, who in prison participate in programs designed to make them more employable, and once released from prison, are in fact 40% more likely over the next 5-years than they were prior to prison to get work and raise their earnings. Among this group, the likelihood of reoffending within 5 years is cut in half (by 46%). In contrast, the effect of Norwegian prisons on those employed before they went to prison is negligible. 

The evidence suggest that in Norway prison works only because it is an effective job training program for the unemployed.

The success of Norwegian prisons may well extend to other Scandinavian countries, which also have low rates of imprisonment and share a similar penal culture (Pratt. 2008). However, we know of no evidence as good as the evidence provided in (Bhuller, Dahl, Løken and Mogstad 2016) for the positive effect of some prisons on recidivism.

Prison is probably no more effective than non-custodial sentences

One large systematic review of evidence considered over 3,000 relevant studies done in western countries, filtered out those that were not sufficiently rigorous and was left with around 300 studies (Villettaz, Gillieron and Killias. 2015). The authors of the review found that the rate of re-offending after a non-custodial sanction is lower than after a custodial sanction in most comparisons. However, they were unable to rule out the possibility that this was due to insufficient control of pre-intervention differences between prisoners and those serving “alternative” sanctions. In other words, it might be that the difference uncovered in the multiple studies is not explained by the nature of the sanction – custodial or non-custodial – but by the nature of those undergoing the sanction, say, more or less inclined to offend.

Longer prison sentences have no more effect on reoffending than shorter sentences

Studies find no significant effect, positive or negative, of longer prison terms on recidivism rates (Alaska Criminal Justice Commission. 2015 at 10; Meade, Steiner, Makarios and Travis. 2012).

One study of a large population of Italian offenders released under Italian peanl policy reforms, found that most of any deterrence effect is derived from the first few years in prison (Mastrobuni, Giovanni and David A Rivers. 2016.). In 2006, in an attempt to reduce prison overcrowding, more than 20,000 prisoners were released from Italian prisons.  Prisoners were released but with the condition that if they were later caught breaking the law, the unserved portion of their sentence would be added to the new one. This was a kind of natural expereiment as it meant that similar people faced shorter or longer sentences for future crimes, depending on how much time they had left on their existing sentence when released. Were people facing longer sentences less likely to reoffend? The answer is yes, but that on average the effect is limited.  

There is no fixed relationship between the size of the prison population and criminal activity

Prior to looking at the evidence it is perhaps natural to think that there must be a strong link between the extent of criminal activity and the size of the prison population. In fact, the evidence suggests no such link. Crime rates change for complex and poorly understood reasons.

This does not stop us telling plausible sounding stories. When the prison population is growing as it has been in New Zealand, the natural story is either “There is more crime than there was and that is why there is more people in prison than there was” or “There is less crime than there used to be and that is because we are putting more people in prison than we used to”. In New Zealand before the early 1990s, both the prison population and the recorded crime rate were going up, so it was easy to tell the first story. Since the early 1990s, the prison population has continued to go up while the recorded crime rate has gone down, so the second story is now easy to tell.

Easy to tell but hard to explain. The obvious mechanism which would explain it – prison deters and reforms – is, as we saw above, unconvincing when you consider the data on re-offending after prison. (If prison reduces crime why is the level of re-offending among ex-prisoners so high?) 

Likewise, if social and economic factors are as important as argued above, then if it exists, the causal link between more people in prison and less crime is at least going to be a bit scrambled. At the least socio-economic factors will play a significant mediating role between prison and crime.

International evidence does not support the theory of a strong link between prison and crime. New Zealand was one of a number of western industrialized countries that saw a fall in the recorded crime rate in the early 1990s. In these same countries, until the 1990s, ever-increasing crime rates were the accepted normal for the post-World War II period. A review of research looking at these falls in recorded crime rates in early to mid 1990s could find no evidence that they were explained by rates of imprisonment (Farrell, Tilly, Tseloni and Mailley. 2010).

The exception was the United States, where high imprisonment rates may have had a small impact on crime rates. A more recent effort by the National Research Council to assess the extensive US evidence came to a similarly weak conclusion: “The increase in incarceration may have caused a decrease in crime, but the magnitude of the reduction is highly uncertain and the results of most studies suggest it was unlikely to have been large”(NRC. 2014 at 4).

From 2010 to 2015, across the 44 US states where the crime rate declined, imprisonment-rate changes ranged from 13.5% increase to a 25.2% decrease.  In the United States overall from 2010 to 2015, the US prison population rate fell 8.4% and the combined violent and property crime rate declined 14.6% (PEW. December 2016). In other words, in the US there is no consistent relationship between prison and crime and it is possible to lower prison rates and crime rates.

Intervening earlier in a person’s life usually pays off more than intervening later

The Opportunities Party wants to raise the Youth Court age from 17 to 20 so that young people 14 to 19 years of age go before the Youth Court. The Youth Court has a more rehabilitative focus than the courts that currently deal with defendants 17-years and older.

The international evidence suggest that young New Zealanders are at greater risk than young people in other countries we would want to compare ourselves with (OECD. 2009). In New Zealand there is a greater risk of teenage pregnancy and abortion, teenage suicide and teenage mental health problems, and teenage crime.

A review of the best scientific evidence on adolescence by a New Zealand taskforce of experts produced Improving the Transition: Reducing Social and Psychological Morbidity During Adolescence (Office of the Prime Minister’s Science Advisory Committee. 2011).  Two of the points in the Executive Summary of what was discovered are particularly relevant to how The Opportunities Party thinks criminal justice should treat young people (Office of the Prime Minister’s Science Advisory Committee. 2011 at 1-2):

Adolescence is now a prolonged period in the human life course. Its length is influenced by the declining age of puberty as child health has improved and by the rising age at which young people are accepted as adults. This has both societal and biological elements, the latter reflecting recent findings that brain maturation is not complete until well into the third decade of life and that the last functions to mature are those of impulse control and judgement. It is therefore inevitable that adolescence is a period of risk-taking and impulsivity. For many children these are basically healthy and transient behaviours, but for too many there are long-term negative consequences. The key issue is what can be done to change the nature of, and reduce the impact of, these behaviours.

In general, most of the risky and impulsive behaviours of adolescence reflect incomplete maturation of self-control and judgement. Accordingly, punitive approaches are less likely to be effective than well-established and validated approaches that attempt to remedy these deficits. There is an inherent conflict between the practical focus on using chronological age to determine rights and obligations and the highly individualistic processes of maturation.

This paragraph is also worth quoting in full (Office of the Prime Minister’s Science Advisory Committee. 2011 at 6):

One of the most significant findings from the field of neuroscience over the last decade has been the observation that some regions of the brain are not functionally mature until the third decade of life. The late-maturing regions of the human brain underpin the processes required for a host of cognitive activities, including attention span, perseverance, planning, problem solving and critical thinking. They also underpin the processes required for self-regulation including impulse control, wisdom, judgement, and forward thinking. Essentially, there is a mismatch or maturity gap between the age of sexual maturation, with its associated changes in brain function leading to greater reward-seeking and sensation seeking, and the level of brain maturation that is required to navigate the risks that come with additional freedom. Greater risk taking is a normal part of that process and that can involve testing the boundaries of the group norms. When the group norms are not well established, or are characterised largely by risky behaviours, exceeding the boundaries may result in transient or permanent harm. Some have suggested that the later part of adolescence represents a new period of development, referred to as ‘emerging adulthood’ that extends until at least the mid-twenties.

The scientific evidence supports The Opportunity Party’s view that justice for adolescents should be more rehabilitative than retributive.

TOP’s criminal justice policy addresses facts and issues that are old news

None of the facts or issues in this paper will be news to anyone who has been paying attention, including officials in the justice sector, and, presumably, ministers in Cabinet. They (or we) know, for example, that New Zealand prisons probably cause crime, that many prisoners are mentally ill or come from disadvantaged origins, the hugely disproportionate (to their numbers in the general population) share of Māori in prison, and the increasing cost of prisons.

Going back to the late 20th century, none of this would surprise Sir Clinton Roper (1918-1994) or anyone who has read his 1989 report, Te Ara Hou: The New Way, now over a quarter of a century old (Roper. 1989). Nor would it surprise the author of About Time, a Corrections report to a cabinet committee in 2001 with a strategy aimed at slowing the growth and, in time, reducing the prison population (Corrections. May 2001). Or Mel Smith, then Ombudsman, who in 2007 wrote a report for the Prime Minister and Parliament on the operation of the justice sector (Smith. 2007).

Why continue with a failed policy whose failure has long been known?




Alaska Criminal Justice Commission. 2015. Justice Reinvestment Report (December 2015). (



Bhuller, Manudeep , Gordon B. Dahl, Katrine V. Løken and Magne Mogstad. 2016. ‘Incarceration, Recidivism and Employment’, Department of Economics, University of Bergen (July 25). (



Carmichael, Fiona and Robert Ward. 2001. Male unemployment and crime in England and Wales. Economic Letters (October 2001) pp. 111-115. (


Caspi, Avshalom, Renate M Houts, Daniel W Belsky and Honalee Harrington et al. 2016. ‘Childhood forecasting of a small segment of the population with large economic burdens’. Nature Human Behaviour.


[Corrections] Department of Corrections. May 2001. About Time: Turning people away from a life of crime and reducing re-offending. (


[Corrections] Department of Corrections. 2016. 2015/16 Annual Report, Appendix Two: Recidivism Index.


[CSC] Correctional Service Canada. N.d. Aboriginal community development in corrections, ‘What is the rational for sections 81 and 84?’. (


Cullen, Francis T, Cheryl Leo Jonson and Daniel S Nagin. 2011. ‘Prisons do not reduce recidivism: The high cost of ignoring science’ The Prison Journal 91(3) 48S-65S at p. 53S.

( T)




Farrell, G., Tilly, N., Tseloni, A., and Mailley, J. 2010. ‘Explaining and sustaining the crime drop: Clarifying the role of opportunity-related theories’, Crime Prevention and Community Safety (2010) 12, 24 – 41.


Fergusson, David M and Nicola R Swain. 2004. How does economic disadvantage lead to crime, Journal of Child Psychology and Psychiatry, August 2004.



Indig, Devon, Craig Gear and Kay Wilhelm. 2016. Comorbid substance use disorders and mental health disorders among New Zealand prisoners. Department of Corrections. (



Mastrobuni, Giovanni and David A Rivers. 2016. Criminal Discount Factors and Deterrence. ( or


Meade, Benjamin, Benjamin Steiner, Mathew Makarios and Lawrence Travis. 2012. “Estimating a Dose-Response Relationship Between Time Served in Prison and Recidivism”. (


[MoJ] Ministry of Justice, Criminal Justice Policy Group. 1998. The Use of Imprisonment in New Zealand.



Nadesu, Arul. 2009. Reconviction patterns of released prisoners:

A 60-months follow-up analysis. Department of Corrections. (


[NRC] National Research Council. 2014. The Growth of Incarceration in the United States: Exploring Causes and Consequences. National Academies Press, Washington, D.C.


[NZCSS] The New Zealand Crime and Safety Survey. 2008. (


[NZCSS] The New Zealand Crime and Safety Survey. 2013. (



OECD. 2009. Doing Better for Children. (


Office of the Correctional Investigator. N.d. Aboriginal Offenders - A Critical Situation.



Office of the Prime Minister’s Science Advisory Committee. 2011. Improving the Transition: Reducing Social and Psychological Morbidity During Adolescence. (



Petrosino A, Turpin-Petrosino C, Hollis-Peel M, Lavenberg JG.2013. Scared Straight and Other Juvenile Awareness Programs for Preventing Juvenile Delinquency: A Systematic Review.Campbell Systematic Reviews 2013:5.


[PEW] The PEW Charitable Trusts. December 2016. National Imprisonment and Crime

Rates Continue to Fall: Crime dropped faster in 2015 in states with larger prison declines (


Pratt, John. 2008. Scandinavian Exceptionalism in an Era of Penal Excess. British Journal of Criminology (2008) 48, 119-137.



Roper, Clinton. 1989. Ministerial Committee of Inquiry into the Prisons System. Prison Review. Te Ara Hou: The New Way, Crown: Wellington.



Smith, Mell, Ombudsman. 2007. Investigation into issues involving the administration of the criminal justice. (



Tonry, Michael. 2014. Why Crime Rates Are Falling throughout the Western World. 43 Crime & Just. 1 (2014). (


Törnudd, P. 1993. Fifteen Years of Decreasing Prisoner Rates in Finland, A report presented to a Study Group from Western Australia in 1991 with a Postscript 5 November 1993, National Research Institute of Legal Policy: Helsinki.



Villettaz, Patrice, Gwladys Gillieron and Martin Killias. 2015. The effects on Re-offending of Custodial vs. non-custodial Sanctions: An updated Systematic Review of the State of Knowledge. Campbell Systematic Reviews.



Wilkinson, Richard G. and Kate Pickett. 2010. The Spirit Level: Why equality is better for everyone. Penguin.



[i] See the graph at the Equality Trust page Imprisonment at  Also, Wilkinson and Pickett.  (2010) The Spirit Level. Penguin.


[ii] A consistent findings across offending in different countries is what has been called the age-crime curve. The age-crime curve represents the relationship between age and crime as an asymmetrical bell shape. The prevalence of offending in a population tends to increase from late childhood, peaks in the teenage years (around ages 15–19), and then declines from the early 20s, with a long tail.


[1] ‘Average’ has several meanings. In this case the median is intended, not the mean. The mean is determined by adding all the data points in a population and then dividing the total by the number of points. The median is the item in the middle of a list of ranked items. Median is often better than the mean as an indicator of what is average because it is less sensitive to outliers. Among the prison populations in the OECD countries, the US is an outlier.


[1] The full description of the budget category in the 2017/18 Vote Corrections is that it is “for the provision of custodial services including long-term service contracts and Public Private Partnerships for offenders lawfully required to be detained in custody. This includes remand prisoners (people awaiting trial and offenders convicted but not yet sentenced), those offenders sentenced to imprisonment, and any other offenders required to be lawfully detained in custody.”




[1] Department of Corrections, Prison statistics  (


[1] The calculation is as follows: Maori are currently about 5,000 out of a prison population of 10,000. If they were 1,500 –  which is 15% of 10,000 – the total prison population would be 5,000 + 1,500, which equals 6,500.


[1] Our history:


[1] See the graph at the Equality Trust page Imprisonment at  Also, Wilkinson and Pickett.  (2010) The Spirit Level. Penguin.


[1] A consistent findings across offending in different countries is what has been called the age-crime curve. The age-crime curve represents the relationship between age and crime as an asymmetrical bell shape. The prevalence of offending in a population tends to increase from late childhood, peaks in the teenage years (around ages 15–19), and then declines from the early 20s, with a long tail.