Key findings from the drug use careers of offenders (DUCO) study

Foreword | This paper examines the illegal drug using and criminal careers of participants in the Drug Use Careers of Offenders (DUCO) project. The project surveyed 2,135 adult male offenders who were incarcerated in prisons in Queensland, Western Australia, Tasmania, and the Northern Territory in mid-2001.

The present study forms a summary of key findings from a larger report to the Australian Government Attorney General's Department (Makkai and Payne 2003). It focuses on the development of the criminal career, drawing comparisons among regular offenders of different offence typologies, and comments on a variety of risk factors associated with offending. It explores the intersection of drug use and criminal behaviour and estimates that 39 percent of all offenders causally attributed alcohol and/or illegal drugs to the offence/s for which they were then incarcerated.

Toni Makkai
Acting Director

Australian and international criminological research on the links between drugs and crime have both consistently reported three empirical findings:

• most offenders (who come to the attention of the criminal justice system) have used illegal drugs;
• minor offending precedes drug use; and
• offenders who are drug users are more likely to report higher rates of offending.

While there is consensus in the literature that indicates the existence of a relationship between drugs and crime, the nature of this relationship remains highly contested. In recent years, researchers are more commonly concluding that the link between these two phenomena varies according to a number of environmental, situational and psychological factors. In brief, White and Gorman (2000) provide three basic explanatory models to help define this relationship:

• substance use leads to crime;
• crime leads to substance use; and
• substance use and crime are caused by the same factors.

In terms of Australian research, there has been only one major published quantitative study, in New South Wales, on the links between drugs and crime. The focus of this study was primarily on the relationship between heroin use and property crime (Dobinson and Ward 1986). In addition to this there has been a major qualitative study of violent property offenders conducted in Western Australia (Indermaur 1995). The general paucity of Australian research on the drug use patterns of incarcerated offenders illustrates the gap in the evidence base that focuses on drug use among the most serious and frequent criminal offenders.

The DUCO study examines the lifetime offending and drug use careers of adult sentenced male inmates in four Australian jurisdictions - Queensland, Western Australia, Tasmania, and the Northern Territory. It is proposed to survey adult females and male and female juveniles in 2003-04.

Research purpose and method

The purpose of the DUCO research is to further inform the evidence base for drug policy by quantifying the links between illegal drug sand crime.

Data collection was conducted between December 2000 and June 2001, and the response rate was 73 percent; this is higher than most other inmate surveys. This research represents a significant improvement in the evidence base as it:

• covers a wide range of offence types, not just property offending;
• explores most major legal and illegal drugs, not just heroin;
• is a random sample of incarcerated offenders;
• is a significant improvement in sample size on previous Australian research;
• provides information on offenders in four jurisdictions; and
• cross-validates basic self-reported offender information with official administrative records.

About the DUCO male sample

In general terms, offenders in the DUCO male sample tended to be aged in their twenties or thirties, with a mean age of 33 years. They reported low levels of education, had a one in four chance of being Indigenous, and had high levels of prior contact with the criminal justice system.

Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Overall, they had an average of 41 lifetime charges, 34 convictions and 15 sentences to prison across all of the 13 offence types analysed in this study. International and Australian literature has illustrated the significant disparity between offences committed and those that have come to the attention of the criminal justice system (see, for example, Australian Bureau of Statistics 2002). As a result, lifetime charges do not reflect the total number of lifetime offences for each offender and thus these figures may underestimate the total volume of offending.

Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Moreover, the number of sentences to prison received by an offender is not equivalent to the total number of times spent in prison, because multiple charges may be sentenced to the one period of imprisonment. On average, however, 90 percent of lifetime charges received by these offenders resulted in a conviction, while 60 percent of convictions resulted in a sentence to prison.

This study found that male incarcerated offenders reported a variety of property and violent offending behaviour throughout their criminal careers. They were also significantly more likely than the general population to have used or regularly used illegal drugs.

Despite this diversity in drug use and offending, it was possible to classify three-quarters of the offenders into a typology of offending or crime types.

These were:

• regular property offenders (27 percent) - offenders who reported having committed property offences regularly but not having committed regular violent crime or fraud;
• regular multiple offenders (15 percent) - offenders who reported committing both property and violent offences regularly but not fraud offences;
• regular violent offenders (8 percent) - offenders who were not regular property or fraud offenders but reported regularly engaging in violent crime;
• regular fraud offenders (8 percent) - offenders who reported regularly engaging in fraud;
• drug sellers (7 percent) - offenders who reported regularly selling illegal drugs but did not commit property crime, violent crime or fraud regularly;
• drug buyers (7 percent) - offenders who reported only regularly buying illegal drugs but committing no other offence type regularly; and
• homicide offenders (5 percent) - offenders who reported having committed a homicide but were not regular offenders of any offence type.

The remaining offenders (24 percent) were non-regular offenders, who did not report regularly engaging in any of the offence types analysed in this study. The rationale for categorising offenders based on self-reported regular offending behaviours is discussed further in the full report (Makkai and Payne 2003).

Offending career

Offenders were asked about their offending behaviour for a range of property, violent and drug offences. The 13 offences included under these three broad offending categories were:

• property offences - stealing without break-in, break and enter, motor vehicle theft, trading in stolen goods, fraud and vandalism;
• violent offences - physical assault, robbery without a weapon, armed robbery, sexual assault and homicide; and
• drug offences - buying illegal drugs and selling illegal drugs.

Overall, the most common crimes reported by offenders were buying illegal drugs, physical assault, and break and enter. The least common were sex offences and homicide. Among the property offences, break and enter was reported by more than half of all offenders within the total sample. More offenders reported lifetime prevalence of physical assault than any other violent offending type. As this is a sample of incarcerated offenders it is not surprising that around three quarters reported having committed three or more of the 13 offences included in the study.

Not all offenders who reported committing a particular offence type escalated to become a regular offender of that offence (see figure 1). Regular offending was self-defined by the offender, and was usedas the primary basis for offender classification. Around one quarter of the sample did not report regular offending for any of the 13 offence types. For the remaining 75 percent, the offence most likely to have been committed regularly was the purchase of illegal drugs, followed by the sale of illegal drugs and break and enter.

Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Escalation, as measured in this study, is the proportion of offenders that progressed from 'ever' to 'regularly' committing a specific offence. The rate of escalation is important because it illustrates which offence types are more likely to be associated with offenders progressing to more frequent and regular offending. Overall, escalation was greatest for drug offences where more than 80 percent of offenders who had ever bought illegal drugs progressed to buying illegal drugs regularly. Among property offences, escalation was greatest for offenders who reported trading in stolen goods (57 percent) and committing a break and enter (55 percent). Despite being the second most prevalent offence among this sample, the rate of escalation for physical assault illustrates that only 23 percent of offenders who had ever committed the offence self-reported regularly engaging in it.

The DUCO male study also revealed two important trends - offenders generally do not engage in only one particular offence type; and offending often occurs across a variety of offence typologies.An example of this is that more than 60 percent of offenders who reported having regularly committed an armed robbery also reported regularly committing physical assault. This was the case for more than 30 percent of offenders who regularly engaged in break and enter.

Key differences between offender types

Regular property offenders are those who reported regularly engaging in property offences but not regularly engaging in violent or fraud offences. They were more likely than regular violent offenders to have bought or sold illegal drugs, highlighting a more active involvement in drug market activity.

Regular property offenders engaged in crime more frequently than regular violent offenders in that they:

• were more likely to have reported ever and regularly committing three or more of the 13 offences;
• reported a greater level of interaction with the criminal justice system - an average of 67 lifetime charges compared with 14 for regular violent offenders; and
• were significantly more likelyto have served time in a juvenile detention centre.

The criminal justice system has traditionally treated violent offending as more serious than property offending or drug possession. However, as is illustrated, regular violent offenders were less likely to have bought or sold illegal drugs, to have committed three or more of the 13 offence types, or to report a high frequency of offending during the six months prior to arrest. Overall, the data suggest that regular violent offenders, while potentially more serious in terms of the offences committed, lead less chronic offending lifestyles than do regular property offenders.

While categorisation of the offending data allowed a comparison of two mutually exclusive offender categories - property offenders and violent offenders - a sub-group of regular multiple offenders (15 percent of the total sample) remained. These offenders were regular offenders of both property and violent offences; they were also the most chronic, frequent and serious offenders within the prison population.

Offending data show that regular multiple offenders:

• more frequently reported lifetime prevalence and regular offending across all property and violent offence types with the exception of the most serious violent offences such as sex offences and homicide;
• were more likely than any other offender type to report committing three or more of the 13 offences regularly;
• were more likely to have ever bought and sold illegal drugs than all other regular offending types; and
• were more likely to have served time in a juvenile detention centre.

Offenders who reported regularly engaging in fraud were not dissimilar to regular property offenders in terms of overall lifetime offending history. They reported similar levels of lifetime prevalence of property and drug offences; however, they were more likely to have regularly traded in stolen goods. Demographic characteristics suggest that fraud offenders were older, less likely to have been in juvenile detention, and were on average more educated. As is confirmed through offending pathways, regular fraud offending does not commence until late in the offending career. This suggests that, in most cases, fraud may simply be a more sophisticated acquisitive crime that occurs after the onset of less serious property offending earlier in the criminal career.

Twenty-four percent of the total incarcerated population comprised non-regular offenders of any of the 13 offence types. In terms of offending histories, they were the least likely to report lifetime prevalence and regular offending across all offence types and appeared to be the least chronic and frequent offenders in the prison system. The most likely reason for their incarceration was the severity of their current most serious offence, which in this case is most likely to be homicide and sex offences.

Drug use career

The majority of offenders reported using illegal drugs and poly-drug use was common. More than 80 percent had used any of the four main drug types - cannabis, heroin, amphetamines and cocaine. Regular illegal drug use during the six months prior to their most recent arrest, defined as current regular use, was reported by 62 percentof offenders.

In terms of the types of drugs, regular use was reported by:

• 53 percent for cannabis;
• 31 percent for amphetamines;
• 21 percent for heroin;
• 7 percent for cocaine; and
• 35 percent for two or more of the above illegal drugs.

Escalation from experimentation to persistent drug use was greatest for offenders who had ever experimented with cannabis, followed by amphetamines and then heroin. Not only was cocaine the drug least likely to have ever been used by this sample of offenders, it was also the drug where escalation from experimentation to persistence occurred less often. By combining all four drugs together, the likelihood of escalation from experimentation to persistence was very high - there was a three in four chance.

Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Measures in the frequency of drug use were also calculated for offenders who were current regular users of each drug. Current regular users of heroin were more likely to report using heroin several times a day when compared with regular amphetamine, cocaine or cannabis users. This is consistent with what is known about the addictive properties of heroin and opiate related substances.

Analysis by offender category reveals significant differences in the type and frequency of drug use over the lifetime criminal career. Regular multiple offenders, regular property offenders and regular fraud offenders (primarily acquisitive crime offenders) consistently reported a greater lifetime prevalence of illegal drug use than did homicide offenders, violent offenders and non-regular offenders. The data suggest that offenders with a more entrenched and chronic offending profile reported higher levels of both experimentation and persistent use of illegal drugs.

Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Regular drug sellers and buyers were non-regular offenders of any offence type other than the buying and selling of illegal drugs. Although their overall offending profile was less significant than regular property or multiple offenders, they reported similar levels of illegal drug use and poly-drug use. Given the nature of their offending profile, it is not surprising that these offenders reported high levels of illegal drug use.

For all offenders within this study, experimentation and regular use of cocaine were both low. By offender type, this trend was consistent with fewer offenders reporting current regular use of cocaine than heroin, amphetamines or cannabis. However, comparisons across offender types illustrate a significant and notable difference.

While the numbers are small, offenders who regularly engaged in fraud offences were far more likely to be a current regular user of cocaine. The escalation rate from experimentation to persistent drug use was 36 percent. This compares to regular violent offenders (the offending group with the next highest escalation rate for cocaine), of which only 26 percent of those who experimented progressed to persistent use.

Linking drugs and crime

Onset and persistence of drugs and crime

The lifetime progression of the criminal career tends in most cases to begin with minor crime, followed by an escalation to regular and more serious forms of offending. For offenders with any history of property offending (76 percent), the criminal career began around the age of 13 years with the first incident of vandalism or stealing without break-in (shoplifting). This was followed by the commencement of more serious offences such as break and enter and motor vehicle theft, graduating to offences such as trading in stolen goods. For offenders with a history of violent offending (75 percent), the first violent offence usually began at around the age of 18 years with assault or robbery without a weapon, followed by more serious forms of violent offending. What is clear about the progression of the criminal career is that in almost all cases where both property and violent offending were evident, property offending commenced at a much younger age than did violent offending. For the few offenders (14 percent) who reported lifetime prevalence of violent offending only, the mean age of first offence (violent) was 25 years - significantly older than the average age of first offence of the total sample. These offenders were significantly more likely to have self-reported more serious violent offences such as sex offences.

Estimates of first and regular drug use include cannabis
Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Estimates are for offenders who reported lifetime prevalence of any drug use.
Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

Estimates are for offenders who report lifetime prevalence of any drug use, including cannabis.
Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

The drug-using career for the DUCO male sample almost invariably commenced with the experimentation of cannabis, followed by amphetamines, heroin and cocaine. The time delay between first cannabis use and the other three drug types was approximately three years. In most cases where persistent cannabis use was evident, regular use also commenced prior to experimentation with other illegal drugs. The average interval between experimentation and persistence for offenders who escalated to regular use was approximately 18 months for each of the four main drug types.

By combining the drug use and criminal career models, analysis shows that of offenders who reported any illegal drug use:

• 17 percent reported using illegal drugs prior to committing any offence;
• 29 percent reported that offending and drug use occurred concurrently, that is within the same year; and
• 54 percent reported initiation into offending prior to any use of illegal drugs.

It is clear that, in general, the lifetime drug using and offending career began with the onset of offending, followed by the onset of illegal drug use, persisting into regular offending, and finally regular illegal drug use. The first offence was most likely to be minor property offending such as stealing without break-in or vandalism, and the drug first used was most likely to be cannabis. By excluding cannabis - so that the mean age of first use of illegal drugs was that of the heavier drugs, heroin, amphetamines or cocaine - the lifetime offending and drug use career commenced with first and regular offending prior to the use of illegal drugs.

It should be noted that, while not the majority, a total of 46 percent of offenders reported experimentation with illegal drugs including cannabis before or concurrently with the onset of offending. While these figures seem to weaken the argument that crime typically occurs before the first use of illegal drugs, the majority of these offenders reported that drug use and offending occurred concurrently; this lends little support to the argument that drugs cause crime. In fact, lifetime progression data indicate that drug use and crime are related primarily to the extent that both behaviours form part of a general deviant lifestyle.

A comparison of the drug using and career offending pathways across offending categories illustrate some other important differences between offending types. The most notable of these are seen in Figure 5, which illustrates the differences between offender types and the proportions reporting that experimentation with illegal drugs occurred prior to offending.

Clearly, regular multiple offenders, regular property offenders and regular fraud offenders were more likely to report that offending commenced prior to the first use of illegal drugs. Conversely, regular drug sellers, homicide offenders and non-regular offenders were more likely to report drug use prior to or concurrent with their first offence. Overall, the trend suggests that offenders who were more active in the criminal market, who had greater contact with the criminal justice system, and who reported more frequent use of illegal drugs were those more likely to have commenced offending prior to illegal drug use. Less chronic offenders - those who began offending at older ages - were more likely to report experimentation with illegal drugs before or concurrent with offending.

The other key difference across each of the offender categories was the ages at which offenders first reported experimentation with illegal drugs. As seen earlier, regular property offenders, regular multiple offenders and regular fraud offenders were more likely to have reported lifetime prevalence of illegal drug use. Pathways data illustrate that these offenders were also more likely to experiment with illegal drugs at an age earlier than violent and non-regular offenders. For regular property offenders, first use began most often with cannabis at the mean age of 14 years. This compares to the mean age of first use reported for regular violent offenders (16 years), homicide offenders (18 years) and non-regular offenders (20 years). Given that for these more chronic offenders the criminal career began before the drug use career, this difference in age indicates that offending type may have hadan impact on an offender's experimentation with, and persistent use of, illegal drugs.

Lifetime effect of drugs on the criminal career

Offenders in this study were asked to comment on the extent to which their personal use of illegal drugs or alcohol has impacted on their lifetime offending career. In terms of understanding the overall impact, of those who reported drug use, 51 percent implicated alcohol or illegal drugs to all or most of their lifetime offending career, while 31 percent stated that alcohol or drugs had no impact. Attributions centred around three explanations:

• drug related economic/compulsive;
• psychopharmacology of drugs; and
• drugs and/or alcohol lead to crime.

Source: Australian Institute of Criminology, DUCO Male Survey, 2001 [Computer File]

It is important to recognise that lifetime career attributions are not necessarily causal attributions. Offenders who reported any drug use were asked how drugs or alcohol affected their lifetime offending career and, if possible, how much of their offending was affected. Attributions varied according to the different offending categories. Regular property offenders and regular fraud offenders were more likely to report the economic compulsive effects of their personal drug use, while violent offenders, homicide offenders and non-regular offenders were more likely to nominate the psychopharmacological effects. These differences were also evident when compared among regular users of heroin and amphetamines, the former, more likely to attribute their offending career to the economic/ compulsive effects of illegal drugs.

Drug market

Analysis of drug market activity prior to incarceration indicates that offenders used a variety of methods to obtain illegal drugs. The most common method was to pay cash, although other methods were also used. Most notably:

• for heroin and amphetamines, around a half reported trading stolen goods, swapping drugs and being paid in drugs for work; just over a third reported trading other goods or recutting the drug;
• for cocaine, around half reported swapping drugs and around a quarter said they recut the drug or received it as payment for work;
• for cannabis, around a quarter reported trading stolen goods, swapping drugs or receiving it as payment for work; and
• in terms of drug expenditure, chronic offenders and those addicted to drugs reported spending more money per week on illegal drugs.

As part of the DUCO male survey, offenders were asked whether they had used violence or threats of violence to obtain illegal drugs. This includes violence towards drug market operators, was well as individual community members in the form of armed robbery or assault where the aim as to obtain money for drugs. Drug market data suggest that violence associated with drug markets in Australia may be larger than first thought, although it is relatively rare around the cannabis market. In terms of amphetamines, 20 percent said they had used force or violence to obtain drugs and eight percent said they also used weapons. The most violence seems to be around heroin markets, with 29 percent reporting the use of force or threats of violence and 17 percent using weapons. There was also violence associated with the cocaine market with 15 percent reporting the use of force or threats and 9 percent reporting that they used weapons.

Risk factors

The main focus of the DUCO male study was an analysis of offending and drug use behaviour among a variety of offending types. However, it is recognised that a number of factors may impact upon an offender's drug use and criminal career. A history of juvenile detention, Indigenous status, addiction and intoxication were analysed as contributing factors. The effects of alcohol use and psycho-stimulants on violent crime are further discussed in the full report.

Juvenile detention

Juvenile detention is a clear marker for the early onset and persistence into both criminal and drug using careers. In general, younger offenders with a history of property offending, regular property offending or fraud offending were more likely to have reported spending time in a juvenile detention centre. Compared to offenders without a history of juvenile detention, they:

• reported a greater number of lifetime charges, convictions and sentences to prison;
• reported a younger age of first and regular offending across all offence types;
• were more likely to have used any drug, regularly used any drug, and used more than one of the four main drug types;
• reported commencing first and regular drug use at a younger age; and
• were more likely to report addiction to any drug.

Indigenous status

Indigenous offenders represented 25 percent of the DUCO male sample. They tended to be over-represented in violent offences. When compared with non-Indigenous offenders, they:

• reported fewer lifetime charges and convictions but similar levels of incarceration to adult detention centres;
• were more likely to have spent time in juvenile detention;
• commenced their offending career at a younger age but their drug use career at an older age; and
• were less likely to have used and regularly used any of the four main drug types.

Addiction and intoxication

Offenders were asked a number of questions relating to addiction and intoxication at the time of the current most serious offence. Overall, addicted offenders were more likely to regularly engage in property and drug offences. They were more likely to report 'hanging out' for illegal drugs at the time of their most serious offence and to attribute illegal drugs to both their most serious offence and lifetime offending career.

Comparisons of addiction data across offender categories indicates that regular multiple offenders, regular property offenders and regular fraud offenders were most likely to report addiction during the six months prior incarceration. Few homicide offenders and non-regular offenders reported an illegal drug addiction during this time. The frequency of offending was not significantly different between offenders addicted to heroin and offenders addicted to amphetamines.

¹ Total estimates are the percentage of offenders where drugs can be causally attributed to the current most serious offence.
Source: Australian Institute of Criminology, DUCO Male Survey 2001 [Computer File]

Intoxication was also measured in this study. Offenders were asked whether at the time of committing the most serious offence, they were 'high' on drugs or 'drunk' on alcohol. Sixty-two percent of the total sample reported intoxication by illegal drugs or alcohol - with 24 percent intoxicated by illegal drugs, 21 percent by alcohol, and 17 percent by both alcohol and illegal drugs.

Estimating drug related crime

Offenders in this study were asked to provide reasons for committing the most serious offence for which they were in prison at the time of the study. Overall, 41 percent reported that their most serious offence was in some way related to illegal drugs or alcohol. Unfortunately, in the majority of these cases offenders stated that illegal drugs or alcohol were related to their offending but failed to clearly articulate the nature of the relationship - for instance intoxication or money for drugs. Without specified attributions it is difficult to differentiate between offences that were caused by illegal drugs and those where illegal drugs were a factor but the relationship was not causal. As a result, a conservative method of estimation was used to calculate the total proportion of offenders where drugs or alcohol could be causally attributed to the current most serious offence. (see Table 4) For an offence to have been caused by illegal drugs or alcohol, the offenders must have: (a) stated that the offences were caused in some way by drugs or alcohol; and (b) have been either intoxicated or addicted to illegal drugs or alcohol at the time of offending.

Twenty nine percent of offenders in DUCO male study causally attributed their current most serious offence to intoxication. Eleven percent attributed intoxication to illegal drugs, ten percent to alcohol, and eight percent to both alcohol and illegal drugs. Comparisons by offender type indicate that the total proportion of offenders where intoxication is causally attributable were similar, with the exception of regular multiple offenders of which 35 percent causally attributed intoxication. The most notable differences between offence types are seen when the data are analysed by drug type. Homicide offenders and non-regular offenders were more likely to attribute intoxication to alcohol, while property, fraud and multiple offenders reported illegal drugs.

Twenty-four percent of offenders in the DUCO male study causally attributed their offending to an alcohol or drug addiction. Eighteen percent attributed addiction to illegal drugs, three percent to alcohol, and three percent to both alcohol and illegal drugs. Unlike intoxication, addiction attributions varied significantly across offender categories. Regular fraud offenders, property offenders and multiple offenders more frequently attributed addiction when compared with homicide offenders and non-regular offenders.

So how much crime can be causally attributed to illegal drugs or alcohol? A combination of both the intoxication and addiction estimates suggest that 39 percent of offenders within the DUCO male sample causally attributed their current most serious offence to illegal drugs or alcohol. That is,39 percent of offenders committed their most serious offence because of these substances. By drug category, illegal drugs were implicated by 18 percent of all offenders, nine percent for alcohol and 12 percent for both alcohol and illegal drugs. These estimates are comparable to the results of research from Canada (Pernanen, Consineau, Brochu and Sun 2002).

By offender category, the proportions of offenders attributing drugs or alcohol was greatest for fraud offenders, followed by regular multiple offenders and regular property offenders. Illegal drugs were most likely to be attributed by these offenders as the cause of their most serious offence. Non-regular offenders and homicide offenders were the groups least likely to have attributed illegal drugs or alcohol, but where attribution was made, alcohol predominated other drugs as having the greatest effect on the most serious offence.

References

• Australian Bureau of Statistics 2002, 'ABS Crime and Justice Data' in A. Graycar and P. Grabosky (Eds.) The Cambridge Handbook of Australian Criminology, Cambridge University Press, Melbourne, pp. 27-51.
• Dobinson, I. and Ward, P. 1985, Drugs and Crime: A Survey of New South Wales Prison Property Offenders, NSW Bureau of Crime Statistics and Research, Sydney NSW.
• Indermaur, D. 1995, Violent Property Offenders, Federation Press, Annandale.
• Pernanen, K., Cousineau, M., Brochu,S. and Sun, F. 2002, Proportions of Crimes Associated with Alcohol and Other Drugs in Canada, Canadian Centre in Substance Abuse, Toronto.
• White, H. and Gorman, D.M. 2000 'Dynamics of the Drug Crime Relationship' in Lafree, G. (Ed.) Criminal Justice 2000: Volume 1: The Nature of Crime: Continuity and Change, NCJ 182408, National Instituteof Justice, USA, pp. 151-218. (http://www.ncjrs.org/criminal_justice2000/vol_1/02d.pdf)

Acknowledgement

The DUCO project is funded by the Australian Government Attorney General's Department under the National Illicit Drugs Strategy, and it is managed by the Australian Institute of Criminology. It represents a major partnership between the Australian Government Attorney General's Department, the Australian Institute of Criminology and the various corrections agencies in the participating jurisdictions.

About the authors

Toni Makkai is the Acting Director of the Australian Institute of Criminology. Jason Payne is a Research Assistant at the Australian Institute of Criminology.