Reducing Repeat Offending Through Less Prosecution in Victoria, Australia: Opportunities for Increased Diversion of Offenders Abstract Research Question How did the use of diversion from prosecution and criminal sentencing change in Victoria, Australia, in the 10 years to 2016/2017, with what estimated effects on repeat offending? Data We tracked 1,163,113 criminal cases brought against both juveniles and adults by police in the state of Victoria, Australia, including 181,836 diversions, during the 10-year time period from the fiscal year of 2007/2008 through 2016/2017. Methods Taking the percentage of all cases diverted in the first year (25.6%), we calculated for each of the study years how many more cases would have been diverted from prosecution across the subsequent 9 years if the diversion rate had stayed the same (“missed opportunities”). We multiplied the estimated number of these “missed opportunities” by the reduced frequency of repeat offences that the prosecuted offenders were likely to have committed, after adjusting for the time at risk by the number of years left in the study period. Then, based on a systematic review of diversion experiments (Petrosino et al. 2010), we applied the standardised effect size of diversion in those studies to Farrington’s (1992) annualised crime frequency per 100 offenders aged 25, multiplying that effect across all of the person-years after a case was prosecuted rather than diverted, using both population-based rates and rates based only on detected offenders at that age. Findings The diversion rate in Victoria dropped in half over 10 years, from 25.6% to 12.5%. The total missed opportunities for diversion, compared to the counterfactual of applying diversion at a constant rate of 25% over that time period, totalled 115,885 cases over the 10 years. Taking an average effect size (d = − 0.232) across seven experiments with a mean follow-up time of 12–13 months, as derived from a systematic review of diversion experiment outcomes, our illustrative estimate is that at least 8 crimes per year per 100 offenders could have been prevented among the missed opportunity cases. Using a population rate of offending, the estimate equals 1474 crimes that could have been prevented. Using the offending population rate, we estimate that 37,050 offences could have been prevented. Conclusions While the exact amount of crime prevented remains speculative, the application of best evidence to the missed opportunity cases suggests that more diversion could have resulted in substantially less repeat offending, and hence less total crime.

Burying the ‘Power Few’: Language and Resistance to Evidence-Based Policing

Tracking Kidnappings in London: Offenders, Victims and Motives Abstract Research Question What was the nature of kidnappings in London during a fairly recent 5-year period in the kinds of victims, offenders, motives, types of violence used and levels of injury? Data We analyse 924 reports of kidnap crimes recorded by the Metropolitan Police Service between 1 April 2006 and 31 March 2011. These data included free text information drawn from case notes. Methods We establish mutually exclusive categories of kidnappings by codifying all crime records, after examining case notes and populated fields from the Metropolitan Police’s crime recording system. Descriptive statistics are used to portray the patterns and nature of these crimes. Findings The application of a typology of mutually exclusive categories for these kidnappings shows that gangland/criminal/drugs-related cases comprised 40.5% of all kidnappings. Another 21% of all kidnaps were domestic or familial, including honour killings. Just over 10% were incidental to ‘acquisitive’ crimes such as car-jacking, whilst 8% were sexually motivated. Only 6% were categorised as traditional ransom kidnappings. About 4% were categorised into a purely violent category, whilst 3% were categorised as international/political. Conclusions The investigative and preventive implications of these many social worlds mapped out by this typology are substantial. Each social context may require investigators to possess expertise in the specific social world of kidnapping, as distinct from what might be called expertise in ‘kidnaps’ per se. Investigations and prevention might be re-engineered around targeted intelligence from these diverse social contexts.

Targeting the Most Harmful Offenders for an English Police Agency: Continuity and Change of Membership in the “Felonious Few” Abstract Research Question How concentrated is the total harm of offences with detected offenders (identified suspects) among the complete list of all detected offenders in a given year in an English police agency, and how consistent is the list of highest-harm “felonious few” offenders from one year to the next? Data Characteristics of 327,566 crimes and 39,545 unique offenders as recorded by Northamptonshire Police in 7 years from 2010 to 2016 provide the basis for this analysis. Methods Crime and offender records were matched to harm weightings derived from the Cambridge Crime Harm Index (Sherman et al. 2016a; Sherman et al., Policing, 10(3), 171–183, 2016b). Descriptive statistics summarize a concentration of harm identifying the felonious few, changes over time in membership of the “few”, offender typologies and tests for escalation of severity, frequency and intermittency across repeated offences. Findings Crime harm is much more concentrated among offenders than crime volume: 80% of crime harm that is identified to an offender is linked to a felonious few of just 7% of all detected offenders. While chronic repeat offenders are the majority contributors to harm totals of this group, those with the most general range of offence types contribute the most harm. Individual members of the felonious few rarely maintain that position year on year; over 95% of each year’s list is composed of individuals not present in previous years. Within individual crime histories, we observe a pattern of de-escalation in crime harm per offence over time. “One-time” offenders, those with just one crime record, typically made up a third of the felonious few in both number and harm contribution. Conclusions These findings demonstrate the potential to target a small number of repeat offenders for harm reduction strategies using a metric of total crime severity, not just volume, despite a substantial portion of crime harm caused by one-time offenders that may be largely unpredictable.

Targeting the Most Harmful Co-Offenders in Denmark: a Social Network Analysis Approach Abstract Research Question Is there a ‘power few’ individuals in Denmark who, through consistent co-offending, produce the highest frequency of crimes and the most harm to society amongst all co-offenders? Data We analysed official statistics from the Police Crime Case Management System in Denmark on all 437,717 charges for violations of the Danish Criminal Code, the Illegal Substances Act and the Weapons Act, in which co-offender relationships were identified from 2007 to 2017, equal to 28% of the national total of all 1,554,943 such charges filed against both solo offenders and co-offenders in that time period. Methods We cross-referenced charging records with crime harm values taken from the Danish Crime Harm Index to measure the severity of all offence types charged. A social network analysis (SNA) algorithm was applied to the data to test for centrality and identify key co-offenders. Findings While 7.5% of the co-offending population accounted for 50% of crime volume, only 3.6% of the co-offenders accounted for 50% of total crime harm. The latter made up just 1.2% of the overall offender population in Denmark, but contributed 24% of overall harm. Social network analysis of how central that power few was in relation to other co-offenders suggests an even smaller cohort of co-offenders—the ‘power few of the power few’—who are disproportionality more connected to other co-offenders. Conclusions The ‘power few’ phenomenon exists in co-offender networks, with a pronounced concentration of harm caused by a small number of co-offenders. The evidence suggests that targeting co-offenders based on social network analysis can enhance the harm potentially reduced by both investigations and crime prevention strategies.

Evidence vs. Professional Judgment in Ranking “Power Few” Crime Targets: a Comparative Analysis Abstract Research question How accurately can local police officers use professional judgement to identify the highest-crime street locations and offenders with the most crime and harm, in comparison to an evidence-based rank-ordering of all possible locations and names derived from police force records? Data A face-to-face survey was conducted in groups with a purposive convenience sample of 123 operational police officers to ask their professional judgement for selecting the ten most crime-prone streets and suspected offenders in their command areas. Separate rankings by crime harm were also requested. Cambridgeshire Constabulary crime and confirmed suspect reports were analysed to create the same lists the officers were asked to provide. Methods The study compared results of surveys of police officers asked to name the top 10 streets and offenders for volume and harm of crimes committed in each policing area to the top ten lists generated by comprehensive and systematic analysis of reported crimes. Findings The top ten lists generated by officers were highly inaccurate compared to the lists produced by comprehensive analysis of crime and charging records. Officers surveyed were 91% inaccurate in naming the most prolific suspected offenders in their areas and 95% inaccurate in naming the most harmful suspected offenders. Officers were slightly less inaccurate in naming the streets in their areas with the highest frequency of crimes (77% incorrect) and the greatest severity of crimes (74% incorrect). Officers in urban areas (N = 42) were substantially more accurate than officers working in semi-rural areas (N = 30) in identifying streets with the highest crime frequency (Cohen’s d = 0.9; p = .00) and highest total harm (Cohen’s d = 1.3; p = .00), but urban officers still failed to name about two-thirds of the most harmful streets. Conclusions Police officers can benefit from evidence-based targeting analysis to help them decide where their proactive and preventive work can be deployed with the greatest benefit.

Forecasting Knife Homicide Risk from Prior Knife Assaults in 4835 Local Areas of London, 2016–2018 Abstract Research Question How accurately can all recorded locations of 97 knife homicides in one year be forecast across all 4835 Lower Layer Super Output Areas (LSOAs) of London, based only upon all 3506 known locations of nonfatal knife injury assaults in the preceding year? Data All recorded “knife crimes” in the Metropolitan Police Service (MPS) area of London in the financial year 2016–2017 (year 1) were manually reviewed to identify all 3506 reported locations of knife-enabled (KE) but nonfatal injuries, as distinct from other events digitally coded as “knife crimes”, such as displaying, threatening with, or carrying knives. All KE homicides in 2017–2018 (year 2) were then added to the database. Methods Each KE injury assault in year 1 was classified for occurrence in one of London’s 4835 LSOAs. The total N of such crimes within each LSOA was summed across all records to divide all LSOAs into seven categories of frequency of KE injury assaults in 2016/2017: 0, 1, 2, 3, 4, 5, and 6 or more. We then divided the N of LSOAs in each category in 2016/2017 (year 1) into the total N of knife homicides in 2017/2018 (year 2). False positives, false negatives, and percentage of homicides targeted were calculated for six different targeting plans. Findings Over two thirds (69%) of KE homicides in 2017/2018 (year 2) occurred in just 67 (1.4%) of all 4835 LSOAs, comprising 3.3% of the 2048 LSOAs that had had one or more of the 3506 KE injury assaults mapped in 2016/2017 (year 1). The proportion of LSOAS with a KE homicide in year 2 was higher where there were higher numbers of KE injury assaults per LSOA in year 1. Among LSOAs with zero assaults in year 1, only 1% had a KE homicide in year 2. Among LSOAs with six or more KE injury assaults in year 1, 15% had a KE homicide in year 2. While the risk of homicide was 1400% higher in the hottest spots of knife assaults than in the coolest spots, the absolute number of year two KE homicides in those hottest areas was only 6% of the total. All LSOAs with one or more year 1 KE assaults had three times as much KE homicide risk than LSOAs with no year 1 KE assaults. Targeting all 2048 areas that had one or more year 1 KE assaults would have yielded a true positive rate of over 3% and covered 69% of actual homicide locations. The true negative rate for 2781 areas that would not have been targeted based on having no year 1 KE injuries would have been 99%. Conclusions Predicting which local areas are most likely to suffer knife-enabled homicides, based only on recent nonfatal knife injuries, can pinpoint risks of homicide in local areas that are up to 1400% higher than in most local areas, offering a range of strategies for resource allocation.

Intimate Partner Homicide in Denmark 2007–2017: Tracking Potential Predictors of Fatal Violence Abstract Research Question What are the characteristics of intimate partner homicide in Denmark that may inform more accurate prediction and prevention of such crimes, and how is knowledge of those facts distributed across families, police and other agencies? Data All Danish police data on all 77 cases of intimate partner homicide (IPH) reported over 11 years (2007 through 2017) in 10 of the 12 Danish Police Districts were coded by the first author, comprising 75% of all known IPH cases in Denmark for those years and 100% of the cases in Districts that allowed access to their investigative files. Methods Potentially predictive variables were selected for coding based on similar studies recently completed in the UK and Australia, with comparisons made between these Danish results and the prior findings. Special emphasis was placed on which potential predictors had been known by some organisation or person, but never reported to police until after the homicides had occurred. Findings Characteristics of IPH cases in this study are remarkably similar to those found in the UK studies, starting with the nearly identical rates of IPH per 100,000. The Danish data show even greater prevalence of male offenders having discussed, threatened or attempted suicide prior to killing their intimate partner (52%) than in the all-England sample (40%). Danish IPH cases were even more likely (71%) than the Thames Valley cases (54%) to have had no prior recorded police contact as a couple before the IPH incident. In Denmark, parties other than the police had prior knowledge of domestic abuse in almost half (47%) of the murders, including public agencies (22% of IPH), but did not share that information with the police. Conclusions In Denmark as in the UK, police have no prior contact with most intimate couples suffering a homicide. While suicidal tendencies are highly prevalent in such cases, police have no legal framework for obtaining intelligence about such risk factors from health and social agencies. These findings show that in Denmark as elsewhere, creating a duty by other public agencies to share information might improve prediction and prevention of domestic homicides.

Implementing a Burglary Prevention Program with Evidence-Based Tracking: a Case Study Abstract Research Questions How was a system of tracking and feedback implemented to achieve a high percentage of treatment delivered as intended to residences targeted for super cocooning, and how successful was the tracking in ensuring implementation of the cocooning program? Data The case study of implementing a tracking system for notifying neighbours of burglary victims is based on intensive tracking of all 43 burglaries in a 2-month summer period in one small area of Greater Manchester. Method The system of tracking featured a written paper and pencil report on each residence visited, with entries audited against GPS records of where each reporting officer was located at the times and places listed in the written report. Body-worn video records were used to triangulate the written and GPS records. The policy tracked was the goal of face-to-face contact with residents of four houses on either side of each burgled residence, plus the initially burgled home, or nine visits per burglary. Results Of the potential 387 homes to visit after each burglary, only 266 occupied dwellings were identified, of which 230 (93%) were visited by Police Community Service Officers (PCSOs) assigned, 141 of them within 2 days after the initial burglary (61%). These visits and second visits resulted in 154 face-to-face discussions warning occupants about an elevated risk of burglary (58%). No contact or leaflet at all was delivered to 12.5% of all potential properties. The case study showed that the tracking and feedback was instrumental in delivering these outputs. Conclusion The time and effort needed for supervisors to track the delivery of an evidence-based, tested crime prevention programme does not exceed supervisory time available, making tracking systems of this kind a feasible element of police business as usual.

Face-to-Face Restorative Justice Conferences for Intimate Partner Abuse: an Exploratory Study of Victim and Offender Views Abstract Research Question In what proportion of intimate partner abuse cases (in which offenders have made some level of formal admission of wrongdoing) would victims, offenders or both be willing to attend a face-to-face restorative justice conference, at least in principle? Data The study included offenders, victims and dyads in 75 low-harm cases of intimate partner abuse (IPA), defined as punishable by 10 or fewer days of Cambridge Crime Harm Index value for the offence. Eligible cases were limited to couples involving a male offender who had admitted responsibility for the harm and a female victim, both age 18 years or over, in cases finalised within 6 months of the incident and with no new incidents since the presenting offence. Of the 75 eligible cases of IPA for which contact was attempted with 150 people, 54 people agreed to grant interviews: 34 victims (45% of those successfully contacted) and 20 offenders (49% of successful contacts) completed interviews, including 13 cases in which both offender and victim in the dyad gave interviews. Method Structured phone interviews were conducted by police officers or staff within 10 months of case reporting. The key feasibility measure was a statement that the interviewee would be ‘likely’ to agree to participate in a face-to-face restorative justice conference (RJC) for crimes in an IPA relationship, based on a 5-point Likert scale. Findings There were 14 (41%) victims and five (25%) offenders who indicated they would likely or definitely be willing to participate in a RJC if one were offered to them now. Seven of the 13 dyads matched on some degree of willingness to participate between both parties. Victims and offenders with some reason for ongoing contact with the other party tended to be more interested in RJCs than those who had severed contact. Victims reporting lower current levels of fear of the offender and who self-reported fewer prior offences were more willing to participate in RJCs. Cases in which victims indicated willingness had more often resulted in a caution than a charge. Conclusions These findings demonstrated an appreciable level of interest in RJCs amongst victims and offenders in IPA cases with low harm. Based on the results of this study, a controlled trial could be considered offering this intervention to couples fitting the eligibility criteria of this study, with emphasis on couples found most likely to accept the offer.