My research focuses on crime analysis topics. This ranges from examining the utility of particular data sets, to developing analytical techniques that can be used to better understand emergent and existing crime problems. Specifically, I apply Environmental Criminology theory, problem-solving processes, and spatio-temporal analysis to create new knowledge that allows crime prevention activities to be devised in response to a crime problem. My PhD research is concerned with identifying the features of the natural, physical and social environment that help to explain temporal patterns in street robbery.
I am passionate about doing translational research which can be used to facilitate knowledge exchange with crime reduction practitioners. I regularly train practitioners in key theoretical concepts and practical techniques that allow them to optimize their analytic outputs. I am the series editor for JDiBrief – an online library of briefing notes on crime, analytical techniques and security topics. Supervisors: Kate Bowers
An evidence-based approach to guide the proposed changes to recruit police training under the Pol... more An evidence-based approach to guide the proposed changes to recruit police training under the Police Education Qualifications Framework (PEQF) in England and Wales requires that changes be grounded in the available evidence on what works in recruit training. This systematic review is a synthesis of primary evidence on police academies, field training, and how police recruits learn. The purpose of the review is to learn from the evidence to inform the development of a graduate level training programme in England and Wales. The review, inspired by a realist approach, includes a total of 33 studies conducted in a number of countries. Key training contexts, mechanisms, and outcomes were examined to determine how training works, under what conditions, and for whom. Findings indicate that student-centred teaching approaches were found to promote critical thinking and problem-solving skills. Recruits preferred practical, hands-on training over theoretical lessons, and field training was consistently shown to have a positive impact on the process of transforming recruits from civilians into police officers. Finally, the role of academic and field training tutors was found to be of critical importance for recruits in integrating theoretical learning with practical skills. Policy implications for the UK College of Policing and police forces implementing the PEQF are discussed.
Policing in the UK is currently undergoing changes to the training and attained qualifications of... more Policing in the UK is currently undergoing changes to the training and attained qualifications of entry level police officers. The College of Policing is in the process of developing three entry routes into the profession, one of which is a graduate conversion course for those new recruits who hold, at a minimum, a Bachelor’s degree. The objective of this research was to gather evidence on existing conversion courses to inform the development of this route. A rapid evidence assessment was undertaken to a narrative synthesis of the literature on graduate conversion courses in other professions. Fifty-one studies were identified and coded. Four main themes emerged from the available evidence as being central. These themes – learning styles, translating theory into practice, teaching methods and assessment were cross cut by pedagogical sub-themes of collaborative learning, and reflective practice. Policy and practice implications for a policing conversion course are drawn out to guide development and delivery of police training and education in the 21st century.
Objectives
To test filter term performance against an original search strategy to identify eviden... more Objectives To test filter term performance against an original search strategy to identify evidence syntheses with a crime reduction outcome in the PsycINFO database, with a view to maximising efficiency and/or effectiveness in the search phase of a systematic review.
Methods A search strategy was developed to identify evidence syntheses with crime reduction outcomes. A ‘quasi-gold standard’ set of 255 relevant studies that were indexed in the PsycINFO database was derived from this initial work and was used to test various filter terms available in the database using the relative recall method. Precision and sensitivity statistics were generated for each search strategy.
Results Seven search strategies were tested using three clusters of index terms, on (1) method filter terms, (2) topic filter terms and (3) method and topic filter terms. These were applied as filters for the original search strategy and, to facilitate comparison, against all records in PsycINFO. The most sensitive filter scored 74.1%, the most precise scored 44.1% and the best compromise between sensitivity and precision scored 53.7% sensitivity and 16.3% precision.
Conclusions Filter term performance in PsycINFO can be used to inform search strategies used within criminology and allied fields for systematic reviews. The variety of filter terms tested here, in the absence and presence of a keyword search, caters for researchers with different information requirements. Using an evidence-based approach to systematic searching can yield considerable resource savings in conducting a systematic review.
This article presents a map and summary of the landscape of a systematic search of the police rec... more This article presents a map and summary of the landscape of a systematic search of the police recruit training literature. Following the process of searching, screening, and coding both published and grey literature, a total of 109 studies met our inclusion criteria. Thematic analysis of the 109 studies led to the emergence of six broad themes and associated subthemes. The two most prevalent themes focused on ‘examining academic and/or field training’ and ‘examining a specific aspect of the training programme’, each containing 36 studies. Most of the studies were based in the USA, (n = 67). Grey literature such as dissertations, theses, and reports made up nearly half of all included studies (n = 51) and published journal articles made up the bulk of the remaining studies (n = 50). Furthermore, 56 studies (50%) used a quantitative design, 36 studies (33%) adopted mixed methods, and 19 studies (17%) employed a qualitative approach. The 109 studies were double-blind quality appraised using recognized quality appraisal tools and revealed a wide variation in the nature and quality of studies. Overall, the strength of the evidence was fragile; only 13 studies (12%) were of a ‘strong’ quality, 55 studies (50%) were ‘weak’, and the rest (41, i.e. 38%) were of ‘moderate’ quality. The article concludes with recommendations for guiding future research in police recruit training.
This paper explored how city-level changes in routine activities were associated with changes in frequencies of police searches using six years of police records from the London Metropolitan Police Service and the New York City Police Department. Routine activities were operationalised through selecting events that potentially impacted on (a) the street population, (b) the frequency of crime or (c) the level of police activity. OLS regression results indicated that routine activity variables (e.g. day of the week, periods of high demand for police service) can explain a large proportion of the variance in search frequency throughout the year. A complex set of results emerged, revealing cross-national dissimilarities and the differential impact of certain activities (e.g. public holidays). Importantly, temporal frequencies in searches are not reducible to associations between searches and recorded street crime, nor changes in on-street population. Based on the routine activity approach, a theoretical police-action model is proposed.
Objectives: A defining feature of a systematic review is the data collection; the assembling of a... more Objectives: A defining feature of a systematic review is the data collection; the assembling of a meticulous, unbiased, and reproducible set of primary studies. This requires specialist skills to execute. The aim of this paper is to marshal tacit knowledge, gained through a systematic search of the crime prevention literature, to develop a ‘how-to guide’ for future evidence synthesists in allied fields.
Methods: Empirical results from a recent systematic search for evidence in crime prevention are supplied to illustrate key principles of information retrieval.
Results: Difficulties in operationalizing a systematic search are expounded and possible solutions discussed. Empirical results from optimizing the balance between sensitivity and precision with the criminological literature are presented. An estimation of database overlap for crime prevention studies is provided to guide other evidence synthesists in streamlining the search process.
Conclusions: A high-quality search will involve a substantial time investment in honing the research question, specifying the precise scope of the work, and trialing and testing of search tactics. Electronic databases are a lucrative source of eligible studies, but they have important limitations. The diversity of expression across the criminological literature needs to be captured by the use of many search terms—both natural language and controlled vocabulary—in database searches. Complementary search tactics should be employed to locate eligible studies without common vocabulary. Grey literature should be ardently pursued, for it has a central role in the crime prevention evidence base.
Background Many local authorities in England and Wales have reduced street lighting at night to s... more Background Many local authorities in England and Wales have reduced street lighting at night to save money and reduce carbon emissions. There is no evidence to date on whether these reductions impact on public health. We quantified the effect of 4 street lighting adaptation strategies (switch off, part-night lighting, dimming and white light) on casualties and crime in England and Wales.
Methods Observational study based on analysis of geographically coded police data on road traffic collisions and crime in 62 local authorities. Conditional Poisson models were used to analyse longitudinal changes in the counts of night-time collisions occurring on affected roads during 2000–2013, and crime within census Middle Super Output Areas during 2010–2013. Effect estimates were adjusted for regional temporal trends in casualties and crime.
Results There was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night. There was significant statistical heterogeneity in the effects on crime estimated at police force level. Overall, there was no evidence for an association between the aggregate count of crime and switch off (RR 0.11; 95% CI 0.01 to 2.75) or part-night lighting (RR 0.96; 95% CI 0.86 to 1.06). There was weak evidence for a reduction in the aggregate count of crime and dimming (RR 0.84; 95% CI 0.70 to 1.02) and white light (RR 0.89; 95% CI 0.77 to 1.03).
Conclusions This study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.
Although the relationship between weather and crime has been extensively investigated over the pa... more Although the relationship between weather and crime has been extensively investigated over the past century, little consensus has emerged on the directions of the relationships observed and the mechanisms through which weather might exert its influence. This paper advances an argument that the interpretation of weather, and subsequent activities based on that interpretation, leads to spatio-temporal variations in criminal opportunities, and hence crime.
Two hypotheses relating to unseasonal weather and effects of weather on discretionary activities are proposed. Negative binomial regression models are used to test these at the 6-hour shift unit of analysis on street robberies in the Strathclyde region of Scotland. In line with predictions, in this temperate microclimate, more favourable weather in winter (higher temperatures and low wind speeds) was associated with increases in robbery. Partial support was also found for the hypothesis regarding time delineated for discretionary activities. Here, temperature, wind speed and humidity were seen to be significant predictors of robbery during the night shift and weekends. Notably rain was shown to have a negative relationship with robbery at the weekends. This affirms that people are less likely to venture outdoors when it is raining when travel behaviour is optional. Counter to our hypothesised effects, fog was the only variable to significantly interact with public holidays. We conclude by discussing how these analyses might be extended and briefly discuss implications for crime prevention.
In many disciplines there is a wealth of primary evaluation research on what works, and systemati... more In many disciplines there is a wealth of primary evaluation research on what works, and systematic reviews that synthesize that evidence. This is, of course, extremely positive. However, the sheer scale of the information and the way in which it is indexed and presented can mean that it is difficult for practitioners to locate the best available evidence. For this reason, in health, education, and other disciplines, using techniques from Information Science, researchers have systematically assembled databases such as those hosted on healthevidence.org and educationendowmentfoundation.org which bring together the most reliable evidence. Hitherto, no such database has existed for crime and criminal justice interventions. This article sets out some of challenges and early findings of one exercise which aims to produce such a database, being completed as part of the What Works Centre for Crime Reduction (WWCCR) initiative in collaboration with the College of Policing.
In the United Kingdom, since 2011 data regarding individual police recorded crimes have been made... more In the United Kingdom, since 2011 data regarding individual police recorded crimes have been made openly available to the public via the police.uk website. To protect the location privacy of victims these data are obfuscated using geomasking techniques to reduce their spatial accuracy. This paper examines the spatial accuracy of the police.uk data to determine at what level(s) of spatial resolution – if any – it is suitable for analysis in the context of theory testing and falsification, evaluation research, or crime analysis. Police.uk data are compared to police recorded data for one large metropolitan Police Force and spatial accuracy is quantified for four different levels of geography across five crime types. Hypotheses regarding systematic errors are tested using appropriate statistical approaches, including methods of maximum likelihood. Finally, a “best-fit” statistical model is presented to explain the error as well as to develop a model that can correct it. The implications of the findings for researchers using the police.uk data for spatial analysis are discussed.
Objectives: Test the influence of darkness in the street robbery crime event alongside temperatur... more Objectives: Test the influence of darkness in the street robbery crime event alongside temperature. Methods: Negative binomial regression models tested darkness and temperature as predictors of street robbery. Units of analysis were four 6-hr time intervals in two U.K. study areas that have different levels of darkness and variations of temperature throughout the year. Results: Darkness is a key factor related to robbery events in both study areas. Traversing from full daylight to full darkness increased the predicted volume of robbery by a multiple of 2.6 in London and 1.2 in Glasgow. Temperature was significant only in the London study area. Interaction terms did not enhance the predictive power of the models. Conclusion: Darkness is an important driving factor in seasonal variation of street robbery. A further implication of the research is that time of the day patterns are crucial to understanding seasonal trends in crime data.
Reducing re-offending amongst ex-prisoners is of paramount importance for both penal and societal... more Reducing re-offending amongst ex-prisoners is of paramount importance for both penal and societal reasons. This paper advances an argument that the current prisoner risk assessment instruments used in the UK neglect to account for environmental determinants of re-offending. We frame this position within the growing literature on the ecology of recidivism, and use the principles of environmental criminology to stress the importance of the opportunities for crime that are present in an ex-prisoners’ neighbourhood. We conclude by considering the implications for policy and discuss how these might conflict with the practical realities of managing ex-prisoners.
Since December 2008, police forces in the UK have published crime statistics using an online crim... more Since December 2008, police forces in the UK have published crime statistics using an online crime mapping tool (www.police.uk). The drivers behind this were to help improve the credibility and confidence that the public had in police-recorded crime levels, address perceptions of crime, promote community engagement and empowerment, and support greater public service transparency and accountability. This article captures the policy rationale behind this initiative, and draws together the research evidence on its impact. We argue that many of the original objectives relating to improving engagement and empowerment have yet to be realized, poor cartographic discipline has led to misinterpretation and confusion, and that the initiative instead has primarily become a tool for promoting political transparency. We suggest that future focus should be on improving the quality and cartographic visualization of the published information alongside the integration of social media functionality to enrich local dialogue on crime issues.
The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear ... more The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear events can be problematic. Network-constrained data (for example transport-related crime) require a different approach to visualize concentration. We propose a methodology called Hot Routes, which measures the risk distribution of crime along a linear network by calculating the rate of crimes per section of road. This method has been designed for everyday crime analysts, and requires only a Geographical Information System (GIS), and suitable data to calculate. A demonstration is provided using crime data collected from London bus routes.
The illegal treatment and trade of waste is an international problem which is widely assumed to b... more The illegal treatment and trade of waste is an international problem which is widely assumed to be both evolving and growing. Emergent forms of criminality such as this often have the problem of data being in scarce supply, and as a result are difficult to study, and subsequently understand. In this paper we introduce the methodological concept of script analysis to assist a more objective assessment and understanding of illegal waste activity. This includes using crime scripts in two ways; to help identify data requirements, and as a tool to analyse illegal waste processes. We illustrate the utility of this methodology using waste electrical and electronic equipment. In doing so, we argue that this approach elicits a specific, focused account of what illegal activity has occurred, and nests it within the wider context of the waste management system. We anticipate that using this methodology will provide academics and practitioners a means of enhancing the investigation, detection and prevention of illegal waste activity.
Hotspot mapping is a popular analytical technique that is used to help identify where to target p... more Hotspot mapping is a popular analytical technique that is used to help identify where to target police and crime reduction resources. In essence, hotspot mapping is used as a basic form of crime prediction, relying on retrospective data to identify the areas of high concentrations of crime and where policing and other crime reduction resources should be deployed. A number of different mapping techniques are used for identifying hotspots of crime – point mapping, thematic mapping of geographic areas (e.g. Census areas), spatial ellipses, grid thematic mapping and kernel density estimation (KDE). Several research studies have discussed the use of these methods for identifying hotspots of crime, usually based on their ease of use and ability to spatially interpret the location, size, shape and orientation of clusters of crime incidents. Yet surprising, very little research has compared how hotspot mapping techniques can accurately predict where crimes will occur in the future. This research uses crime data for a period before a fixed date (that has already passed) to generate hotspot maps, and test their accuracy for predicting where crimes will occur next. Hotspot mapping accuracy is compared in relation to the mapping technique that is used to identify concentrations of crime events (thematic mapping of Census Output Areas, spatial ellipses, grid thematic mapping, and KDE) and by crime type – four crime types are compared (burglary, street crime, theft from vehicles and theft of vehicles). The results from this research indicate that crime hotspot mapping prediction abilities differ between the different techniques and differ by crime type. KDE was the technique that consistently outperformed the others, while street crime hotspot maps were consistently better at predicting where future street crime would occur when compared to results for the hotspot maps of different crime types. The research offers the opportunity to benchmark comparative research of other techniques and other crime types, including comparisons between advanced spatial analysis techniques and predic-tion mapping methods. Understanding how hotspot mapping can predict spatial patterns of crime and how different mapping methods compare will help to better inform their application in practice.
An evidence-based approach to guide the proposed changes to recruit police training under the Pol... more An evidence-based approach to guide the proposed changes to recruit police training under the Police Education Qualifications Framework (PEQF) in England and Wales requires that changes be grounded in the available evidence on what works in recruit training. This systematic review is a synthesis of primary evidence on police academies, field training, and how police recruits learn. The purpose of the review is to learn from the evidence to inform the development of a graduate level training programme in England and Wales. The review, inspired by a realist approach, includes a total of 33 studies conducted in a number of countries. Key training contexts, mechanisms, and outcomes were examined to determine how training works, under what conditions, and for whom. Findings indicate that student-centred teaching approaches were found to promote critical thinking and problem-solving skills. Recruits preferred practical, hands-on training over theoretical lessons, and field training was consistently shown to have a positive impact on the process of transforming recruits from civilians into police officers. Finally, the role of academic and field training tutors was found to be of critical importance for recruits in integrating theoretical learning with practical skills. Policy implications for the UK College of Policing and police forces implementing the PEQF are discussed.
Policing in the UK is currently undergoing changes to the training and attained qualifications of... more Policing in the UK is currently undergoing changes to the training and attained qualifications of entry level police officers. The College of Policing is in the process of developing three entry routes into the profession, one of which is a graduate conversion course for those new recruits who hold, at a minimum, a Bachelor’s degree. The objective of this research was to gather evidence on existing conversion courses to inform the development of this route. A rapid evidence assessment was undertaken to a narrative synthesis of the literature on graduate conversion courses in other professions. Fifty-one studies were identified and coded. Four main themes emerged from the available evidence as being central. These themes – learning styles, translating theory into practice, teaching methods and assessment were cross cut by pedagogical sub-themes of collaborative learning, and reflective practice. Policy and practice implications for a policing conversion course are drawn out to guide development and delivery of police training and education in the 21st century.
Objectives
To test filter term performance against an original search strategy to identify eviden... more Objectives To test filter term performance against an original search strategy to identify evidence syntheses with a crime reduction outcome in the PsycINFO database, with a view to maximising efficiency and/or effectiveness in the search phase of a systematic review.
Methods A search strategy was developed to identify evidence syntheses with crime reduction outcomes. A ‘quasi-gold standard’ set of 255 relevant studies that were indexed in the PsycINFO database was derived from this initial work and was used to test various filter terms available in the database using the relative recall method. Precision and sensitivity statistics were generated for each search strategy.
Results Seven search strategies were tested using three clusters of index terms, on (1) method filter terms, (2) topic filter terms and (3) method and topic filter terms. These were applied as filters for the original search strategy and, to facilitate comparison, against all records in PsycINFO. The most sensitive filter scored 74.1%, the most precise scored 44.1% and the best compromise between sensitivity and precision scored 53.7% sensitivity and 16.3% precision.
Conclusions Filter term performance in PsycINFO can be used to inform search strategies used within criminology and allied fields for systematic reviews. The variety of filter terms tested here, in the absence and presence of a keyword search, caters for researchers with different information requirements. Using an evidence-based approach to systematic searching can yield considerable resource savings in conducting a systematic review.
This article presents a map and summary of the landscape of a systematic search of the police rec... more This article presents a map and summary of the landscape of a systematic search of the police recruit training literature. Following the process of searching, screening, and coding both published and grey literature, a total of 109 studies met our inclusion criteria. Thematic analysis of the 109 studies led to the emergence of six broad themes and associated subthemes. The two most prevalent themes focused on ‘examining academic and/or field training’ and ‘examining a specific aspect of the training programme’, each containing 36 studies. Most of the studies were based in the USA, (n = 67). Grey literature such as dissertations, theses, and reports made up nearly half of all included studies (n = 51) and published journal articles made up the bulk of the remaining studies (n = 50). Furthermore, 56 studies (50%) used a quantitative design, 36 studies (33%) adopted mixed methods, and 19 studies (17%) employed a qualitative approach. The 109 studies were double-blind quality appraised using recognized quality appraisal tools and revealed a wide variation in the nature and quality of studies. Overall, the strength of the evidence was fragile; only 13 studies (12%) were of a ‘strong’ quality, 55 studies (50%) were ‘weak’, and the rest (41, i.e. 38%) were of ‘moderate’ quality. The article concludes with recommendations for guiding future research in police recruit training.
This paper explored how city-level changes in routine activities were associated with changes in frequencies of police searches using six years of police records from the London Metropolitan Police Service and the New York City Police Department. Routine activities were operationalised through selecting events that potentially impacted on (a) the street population, (b) the frequency of crime or (c) the level of police activity. OLS regression results indicated that routine activity variables (e.g. day of the week, periods of high demand for police service) can explain a large proportion of the variance in search frequency throughout the year. A complex set of results emerged, revealing cross-national dissimilarities and the differential impact of certain activities (e.g. public holidays). Importantly, temporal frequencies in searches are not reducible to associations between searches and recorded street crime, nor changes in on-street population. Based on the routine activity approach, a theoretical police-action model is proposed.
Objectives: A defining feature of a systematic review is the data collection; the assembling of a... more Objectives: A defining feature of a systematic review is the data collection; the assembling of a meticulous, unbiased, and reproducible set of primary studies. This requires specialist skills to execute. The aim of this paper is to marshal tacit knowledge, gained through a systematic search of the crime prevention literature, to develop a ‘how-to guide’ for future evidence synthesists in allied fields.
Methods: Empirical results from a recent systematic search for evidence in crime prevention are supplied to illustrate key principles of information retrieval.
Results: Difficulties in operationalizing a systematic search are expounded and possible solutions discussed. Empirical results from optimizing the balance between sensitivity and precision with the criminological literature are presented. An estimation of database overlap for crime prevention studies is provided to guide other evidence synthesists in streamlining the search process.
Conclusions: A high-quality search will involve a substantial time investment in honing the research question, specifying the precise scope of the work, and trialing and testing of search tactics. Electronic databases are a lucrative source of eligible studies, but they have important limitations. The diversity of expression across the criminological literature needs to be captured by the use of many search terms—both natural language and controlled vocabulary—in database searches. Complementary search tactics should be employed to locate eligible studies without common vocabulary. Grey literature should be ardently pursued, for it has a central role in the crime prevention evidence base.
Background Many local authorities in England and Wales have reduced street lighting at night to s... more Background Many local authorities in England and Wales have reduced street lighting at night to save money and reduce carbon emissions. There is no evidence to date on whether these reductions impact on public health. We quantified the effect of 4 street lighting adaptation strategies (switch off, part-night lighting, dimming and white light) on casualties and crime in England and Wales.
Methods Observational study based on analysis of geographically coded police data on road traffic collisions and crime in 62 local authorities. Conditional Poisson models were used to analyse longitudinal changes in the counts of night-time collisions occurring on affected roads during 2000–2013, and crime within census Middle Super Output Areas during 2010–2013. Effect estimates were adjusted for regional temporal trends in casualties and crime.
Results There was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night. There was significant statistical heterogeneity in the effects on crime estimated at police force level. Overall, there was no evidence for an association between the aggregate count of crime and switch off (RR 0.11; 95% CI 0.01 to 2.75) or part-night lighting (RR 0.96; 95% CI 0.86 to 1.06). There was weak evidence for a reduction in the aggregate count of crime and dimming (RR 0.84; 95% CI 0.70 to 1.02) and white light (RR 0.89; 95% CI 0.77 to 1.03).
Conclusions This study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.
Although the relationship between weather and crime has been extensively investigated over the pa... more Although the relationship between weather and crime has been extensively investigated over the past century, little consensus has emerged on the directions of the relationships observed and the mechanisms through which weather might exert its influence. This paper advances an argument that the interpretation of weather, and subsequent activities based on that interpretation, leads to spatio-temporal variations in criminal opportunities, and hence crime.
Two hypotheses relating to unseasonal weather and effects of weather on discretionary activities are proposed. Negative binomial regression models are used to test these at the 6-hour shift unit of analysis on street robberies in the Strathclyde region of Scotland. In line with predictions, in this temperate microclimate, more favourable weather in winter (higher temperatures and low wind speeds) was associated with increases in robbery. Partial support was also found for the hypothesis regarding time delineated for discretionary activities. Here, temperature, wind speed and humidity were seen to be significant predictors of robbery during the night shift and weekends. Notably rain was shown to have a negative relationship with robbery at the weekends. This affirms that people are less likely to venture outdoors when it is raining when travel behaviour is optional. Counter to our hypothesised effects, fog was the only variable to significantly interact with public holidays. We conclude by discussing how these analyses might be extended and briefly discuss implications for crime prevention.
In many disciplines there is a wealth of primary evaluation research on what works, and systemati... more In many disciplines there is a wealth of primary evaluation research on what works, and systematic reviews that synthesize that evidence. This is, of course, extremely positive. However, the sheer scale of the information and the way in which it is indexed and presented can mean that it is difficult for practitioners to locate the best available evidence. For this reason, in health, education, and other disciplines, using techniques from Information Science, researchers have systematically assembled databases such as those hosted on healthevidence.org and educationendowmentfoundation.org which bring together the most reliable evidence. Hitherto, no such database has existed for crime and criminal justice interventions. This article sets out some of challenges and early findings of one exercise which aims to produce such a database, being completed as part of the What Works Centre for Crime Reduction (WWCCR) initiative in collaboration with the College of Policing.
In the United Kingdom, since 2011 data regarding individual police recorded crimes have been made... more In the United Kingdom, since 2011 data regarding individual police recorded crimes have been made openly available to the public via the police.uk website. To protect the location privacy of victims these data are obfuscated using geomasking techniques to reduce their spatial accuracy. This paper examines the spatial accuracy of the police.uk data to determine at what level(s) of spatial resolution – if any – it is suitable for analysis in the context of theory testing and falsification, evaluation research, or crime analysis. Police.uk data are compared to police recorded data for one large metropolitan Police Force and spatial accuracy is quantified for four different levels of geography across five crime types. Hypotheses regarding systematic errors are tested using appropriate statistical approaches, including methods of maximum likelihood. Finally, a “best-fit” statistical model is presented to explain the error as well as to develop a model that can correct it. The implications of the findings for researchers using the police.uk data for spatial analysis are discussed.
Objectives: Test the influence of darkness in the street robbery crime event alongside temperatur... more Objectives: Test the influence of darkness in the street robbery crime event alongside temperature. Methods: Negative binomial regression models tested darkness and temperature as predictors of street robbery. Units of analysis were four 6-hr time intervals in two U.K. study areas that have different levels of darkness and variations of temperature throughout the year. Results: Darkness is a key factor related to robbery events in both study areas. Traversing from full daylight to full darkness increased the predicted volume of robbery by a multiple of 2.6 in London and 1.2 in Glasgow. Temperature was significant only in the London study area. Interaction terms did not enhance the predictive power of the models. Conclusion: Darkness is an important driving factor in seasonal variation of street robbery. A further implication of the research is that time of the day patterns are crucial to understanding seasonal trends in crime data.
Reducing re-offending amongst ex-prisoners is of paramount importance for both penal and societal... more Reducing re-offending amongst ex-prisoners is of paramount importance for both penal and societal reasons. This paper advances an argument that the current prisoner risk assessment instruments used in the UK neglect to account for environmental determinants of re-offending. We frame this position within the growing literature on the ecology of recidivism, and use the principles of environmental criminology to stress the importance of the opportunities for crime that are present in an ex-prisoners’ neighbourhood. We conclude by considering the implications for policy and discuss how these might conflict with the practical realities of managing ex-prisoners.
Since December 2008, police forces in the UK have published crime statistics using an online crim... more Since December 2008, police forces in the UK have published crime statistics using an online crime mapping tool (www.police.uk). The drivers behind this were to help improve the credibility and confidence that the public had in police-recorded crime levels, address perceptions of crime, promote community engagement and empowerment, and support greater public service transparency and accountability. This article captures the policy rationale behind this initiative, and draws together the research evidence on its impact. We argue that many of the original objectives relating to improving engagement and empowerment have yet to be realized, poor cartographic discipline has led to misinterpretation and confusion, and that the initiative instead has primarily become a tool for promoting political transparency. We suggest that future focus should be on improving the quality and cartographic visualization of the published information alongside the integration of social media functionality to enrich local dialogue on crime issues.
The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear ... more The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear events can be problematic. Network-constrained data (for example transport-related crime) require a different approach to visualize concentration. We propose a methodology called Hot Routes, which measures the risk distribution of crime along a linear network by calculating the rate of crimes per section of road. This method has been designed for everyday crime analysts, and requires only a Geographical Information System (GIS), and suitable data to calculate. A demonstration is provided using crime data collected from London bus routes.
The illegal treatment and trade of waste is an international problem which is widely assumed to b... more The illegal treatment and trade of waste is an international problem which is widely assumed to be both evolving and growing. Emergent forms of criminality such as this often have the problem of data being in scarce supply, and as a result are difficult to study, and subsequently understand. In this paper we introduce the methodological concept of script analysis to assist a more objective assessment and understanding of illegal waste activity. This includes using crime scripts in two ways; to help identify data requirements, and as a tool to analyse illegal waste processes. We illustrate the utility of this methodology using waste electrical and electronic equipment. In doing so, we argue that this approach elicits a specific, focused account of what illegal activity has occurred, and nests it within the wider context of the waste management system. We anticipate that using this methodology will provide academics and practitioners a means of enhancing the investigation, detection and prevention of illegal waste activity.
Hotspot mapping is a popular analytical technique that is used to help identify where to target p... more Hotspot mapping is a popular analytical technique that is used to help identify where to target police and crime reduction resources. In essence, hotspot mapping is used as a basic form of crime prediction, relying on retrospective data to identify the areas of high concentrations of crime and where policing and other crime reduction resources should be deployed. A number of different mapping techniques are used for identifying hotspots of crime – point mapping, thematic mapping of geographic areas (e.g. Census areas), spatial ellipses, grid thematic mapping and kernel density estimation (KDE). Several research studies have discussed the use of these methods for identifying hotspots of crime, usually based on their ease of use and ability to spatially interpret the location, size, shape and orientation of clusters of crime incidents. Yet surprising, very little research has compared how hotspot mapping techniques can accurately predict where crimes will occur in the future. This research uses crime data for a period before a fixed date (that has already passed) to generate hotspot maps, and test their accuracy for predicting where crimes will occur next. Hotspot mapping accuracy is compared in relation to the mapping technique that is used to identify concentrations of crime events (thematic mapping of Census Output Areas, spatial ellipses, grid thematic mapping, and KDE) and by crime type – four crime types are compared (burglary, street crime, theft from vehicles and theft of vehicles). The results from this research indicate that crime hotspot mapping prediction abilities differ between the different techniques and differ by crime type. KDE was the technique that consistently outperformed the others, while street crime hotspot maps were consistently better at predicting where future street crime would occur when compared to results for the hotspot maps of different crime types. The research offers the opportunity to benchmark comparative research of other techniques and other crime types, including comparisons between advanced spatial analysis techniques and predic-tion mapping methods. Understanding how hotspot mapping can predict spatial patterns of crime and how different mapping methods compare will help to better inform their application in practice.
Crime Mapping Case Studies: From Research to Practice provides a series of key examples from prac... more Crime Mapping Case Studies: From Research to Practice provides a series of key examples from practice and research that demonstrate applications of crime mapping and its effect in many areas of policing and crime reduction. This book brings together case studies that show how crime mapping can be used for analysis, intelligence development, monitoring performance, and crime detection and is written by practitioners for practitioners.
Leading researchers in the field describe how crime mapping is developing and exposing analytical methodologies and critiquing current practices. Including global case studies that demonstrate a particular application, analytical technique or new theoretical concept, this text offers a truly global overview of this rapidly growing area of interest.
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Papers by Lisa Tompson
To test filter term performance against an original search strategy to identify evidence syntheses with a crime reduction outcome in the PsycINFO database, with a view to maximising efficiency and/or effectiveness in the search phase of a systematic review.
Methods
A search strategy was developed to identify evidence syntheses with crime reduction outcomes. A ‘quasi-gold standard’ set of 255 relevant studies that were indexed in the PsycINFO database was derived from this initial work and was used to test various filter terms available in the database using the relative recall method. Precision and sensitivity statistics were generated for each search strategy.
Results
Seven search strategies were tested using three clusters of index terms, on (1) method filter terms, (2) topic filter terms and (3) method and topic filter terms. These were applied as filters for the original search strategy and, to facilitate comparison, against all records in PsycINFO. The most sensitive filter scored 74.1%, the most precise scored 44.1% and the best compromise between sensitivity and precision scored 53.7% sensitivity and 16.3% precision.
Conclusions
Filter term performance in PsycINFO can be used to inform search strategies used within criminology and allied fields for systematic reviews. The variety of filter terms tested here, in the absence and presence of a keyword search, caters for researchers with different information requirements. Using an evidence-based approach to systematic searching can yield considerable resource savings in conducting a systematic review.
This paper explored how city-level changes in routine activities were associated with changes in frequencies of police searches using six years of police records from the London Metropolitan Police Service and the New York City Police Department. Routine activities were operationalised through selecting events that potentially impacted on (a) the street population, (b) the frequency of crime or (c) the level of police activity. OLS regression results indicated that routine activity variables (e.g. day of the week, periods of high demand for police service) can explain a large proportion of the variance in search frequency throughout the year. A complex set of results emerged, revealing cross-national dissimilarities and the differential impact of certain activities (e.g. public holidays). Importantly, temporal frequencies in searches are not reducible to associations between searches and recorded street crime, nor changes in on-street population. Based on the routine activity approach, a theoretical police-action model is proposed.
Methods: Empirical results from a recent systematic search for evidence in crime prevention are supplied to illustrate key principles of information retrieval.
Results: Difficulties in operationalizing a systematic search are expounded and possible solutions discussed. Empirical results from optimizing the balance between sensitivity and precision with the criminological literature are presented. An estimation of database overlap for crime prevention studies is provided to guide other evidence synthesists in streamlining the search process.
Conclusions: A high-quality search will involve a substantial time investment in honing the research question, specifying the precise scope of the work, and trialing and testing of search tactics. Electronic databases are a lucrative source of eligible studies, but they have important limitations. The diversity of expression across the criminological literature needs to be captured by the use of many search terms—both natural language and controlled vocabulary—in database searches. Complementary search tactics should be employed to locate eligible studies without common vocabulary. Grey literature should be ardently pursued, for it has a central role in the crime prevention evidence base.
Methods Observational study based on analysis of geographically coded police data on road traffic collisions and crime in 62 local authorities. Conditional Poisson models were used to analyse longitudinal changes in the counts of night-time collisions occurring on affected roads during 2000–2013, and crime within census Middle Super Output Areas during 2010–2013. Effect estimates were adjusted for regional temporal trends in casualties and crime.
Results There was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night. There was significant statistical heterogeneity in the effects on crime estimated at police force level. Overall, there was no evidence for an association between the aggregate count of crime and switch off (RR 0.11; 95% CI 0.01 to 2.75) or part-night lighting (RR 0.96; 95% CI 0.86 to 1.06). There was weak evidence for a reduction in the aggregate count of crime and dimming (RR 0.84; 95% CI 0.70 to 1.02) and white light (RR 0.89; 95% CI 0.77 to 1.03).
Conclusions This study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.
Two hypotheses relating to unseasonal weather and effects of weather on discretionary activities are proposed. Negative binomial regression models are used to test these at the 6-hour shift unit of analysis on street robberies in the Strathclyde region of Scotland. In line with predictions, in this temperate microclimate, more favourable weather in winter (higher temperatures and low wind speeds) was associated with increases in robbery. Partial support was also found for the hypothesis regarding time delineated for discretionary activities. Here, temperature, wind speed and humidity were seen to be significant predictors of robbery during the night shift and weekends. Notably rain was shown to have a negative relationship with robbery at the weekends. This affirms that people are less likely to venture outdoors when it is raining when travel behaviour is optional. Counter to our hypothesised effects, fog was the only variable to significantly interact with public holidays. We conclude by discussing how these analyses might be extended and briefly discuss implications for crime prevention.
Keywords: Routine activity approach; Social contact; Discretionary activities; Thermal comfort; Robbery; Micro-temporal; Temperature; Wind speed
public via the police.uk website. To protect the location privacy of victims these data are obfuscated using geomasking
techniques to reduce their spatial accuracy. This paper examines the spatial accuracy of the police.uk data to determine at
what level(s) of spatial resolution – if any – it is suitable for analysis in the context of theory testing and falsification,
evaluation research, or crime analysis. Police.uk data are compared to police recorded data for one large metropolitan Police
Force and spatial accuracy is quantified for four different levels of geography across five crime types. Hypotheses regarding
systematic errors are tested using appropriate statistical approaches, including methods of maximum likelihood. Finally, a
“best-fit” statistical model is presented to explain the error as well as to develop a model that can correct it. The implications
of the findings for researchers using the police.uk data for spatial analysis are discussed.
To test filter term performance against an original search strategy to identify evidence syntheses with a crime reduction outcome in the PsycINFO database, with a view to maximising efficiency and/or effectiveness in the search phase of a systematic review.
Methods
A search strategy was developed to identify evidence syntheses with crime reduction outcomes. A ‘quasi-gold standard’ set of 255 relevant studies that were indexed in the PsycINFO database was derived from this initial work and was used to test various filter terms available in the database using the relative recall method. Precision and sensitivity statistics were generated for each search strategy.
Results
Seven search strategies were tested using three clusters of index terms, on (1) method filter terms, (2) topic filter terms and (3) method and topic filter terms. These were applied as filters for the original search strategy and, to facilitate comparison, against all records in PsycINFO. The most sensitive filter scored 74.1%, the most precise scored 44.1% and the best compromise between sensitivity and precision scored 53.7% sensitivity and 16.3% precision.
Conclusions
Filter term performance in PsycINFO can be used to inform search strategies used within criminology and allied fields for systematic reviews. The variety of filter terms tested here, in the absence and presence of a keyword search, caters for researchers with different information requirements. Using an evidence-based approach to systematic searching can yield considerable resource savings in conducting a systematic review.
This paper explored how city-level changes in routine activities were associated with changes in frequencies of police searches using six years of police records from the London Metropolitan Police Service and the New York City Police Department. Routine activities were operationalised through selecting events that potentially impacted on (a) the street population, (b) the frequency of crime or (c) the level of police activity. OLS regression results indicated that routine activity variables (e.g. day of the week, periods of high demand for police service) can explain a large proportion of the variance in search frequency throughout the year. A complex set of results emerged, revealing cross-national dissimilarities and the differential impact of certain activities (e.g. public holidays). Importantly, temporal frequencies in searches are not reducible to associations between searches and recorded street crime, nor changes in on-street population. Based on the routine activity approach, a theoretical police-action model is proposed.
Methods: Empirical results from a recent systematic search for evidence in crime prevention are supplied to illustrate key principles of information retrieval.
Results: Difficulties in operationalizing a systematic search are expounded and possible solutions discussed. Empirical results from optimizing the balance between sensitivity and precision with the criminological literature are presented. An estimation of database overlap for crime prevention studies is provided to guide other evidence synthesists in streamlining the search process.
Conclusions: A high-quality search will involve a substantial time investment in honing the research question, specifying the precise scope of the work, and trialing and testing of search tactics. Electronic databases are a lucrative source of eligible studies, but they have important limitations. The diversity of expression across the criminological literature needs to be captured by the use of many search terms—both natural language and controlled vocabulary—in database searches. Complementary search tactics should be employed to locate eligible studies without common vocabulary. Grey literature should be ardently pursued, for it has a central role in the crime prevention evidence base.
Methods Observational study based on analysis of geographically coded police data on road traffic collisions and crime in 62 local authorities. Conditional Poisson models were used to analyse longitudinal changes in the counts of night-time collisions occurring on affected roads during 2000–2013, and crime within census Middle Super Output Areas during 2010–2013. Effect estimates were adjusted for regional temporal trends in casualties and crime.
Results There was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night. There was significant statistical heterogeneity in the effects on crime estimated at police force level. Overall, there was no evidence for an association between the aggregate count of crime and switch off (RR 0.11; 95% CI 0.01 to 2.75) or part-night lighting (RR 0.96; 95% CI 0.86 to 1.06). There was weak evidence for a reduction in the aggregate count of crime and dimming (RR 0.84; 95% CI 0.70 to 1.02) and white light (RR 0.89; 95% CI 0.77 to 1.03).
Conclusions This study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.
Two hypotheses relating to unseasonal weather and effects of weather on discretionary activities are proposed. Negative binomial regression models are used to test these at the 6-hour shift unit of analysis on street robberies in the Strathclyde region of Scotland. In line with predictions, in this temperate microclimate, more favourable weather in winter (higher temperatures and low wind speeds) was associated with increases in robbery. Partial support was also found for the hypothesis regarding time delineated for discretionary activities. Here, temperature, wind speed and humidity were seen to be significant predictors of robbery during the night shift and weekends. Notably rain was shown to have a negative relationship with robbery at the weekends. This affirms that people are less likely to venture outdoors when it is raining when travel behaviour is optional. Counter to our hypothesised effects, fog was the only variable to significantly interact with public holidays. We conclude by discussing how these analyses might be extended and briefly discuss implications for crime prevention.
Keywords: Routine activity approach; Social contact; Discretionary activities; Thermal comfort; Robbery; Micro-temporal; Temperature; Wind speed
public via the police.uk website. To protect the location privacy of victims these data are obfuscated using geomasking
techniques to reduce their spatial accuracy. This paper examines the spatial accuracy of the police.uk data to determine at
what level(s) of spatial resolution – if any – it is suitable for analysis in the context of theory testing and falsification,
evaluation research, or crime analysis. Police.uk data are compared to police recorded data for one large metropolitan Police
Force and spatial accuracy is quantified for four different levels of geography across five crime types. Hypotheses regarding
systematic errors are tested using appropriate statistical approaches, including methods of maximum likelihood. Finally, a
“best-fit” statistical model is presented to explain the error as well as to develop a model that can correct it. The implications
of the findings for researchers using the police.uk data for spatial analysis are discussed.
Leading researchers in the field describe how crime mapping is developing and exposing analytical methodologies and critiquing current practices. Including global case studies that demonstrate a particular application, analytical technique or new theoretical concept, this text offers a truly global overview of this rapidly growing area of interest.