Re-counting crime: New methods to improve the accuracy of estimates of crime

There is probably no other scientific endeavour more relevant to the field of Criminology than to count crime accurately. Crime estimates are central to policy. They are used in the allocation of police resources, and more generally they are a central theme of political debate with apparent increases in crime serving as an indictment on existing law and order policies. Academics also make regular use of crime statistics in their work, both seeking to understand why some places and people are more prone to crime, and using variations in crime to help explain other social outcomes. And of course, members of the public also refer to this information. For example, historic crime trends are now included on many house-buying websites.

Currently, there are two main ways of estimating the amount of crime: directly using police records of incidents that they are aware of; and approximating crime using victimisation surveys like the Crime Survey for England and Wales, where a sample of people are asked to report any victimisations in the past year. Theoretical work has highlighted a number of sources of potential error in these data, suggesting that both approaches are deficient. However, we currently lack an empirically robust quantification of the difference sources of error in each. Nor do we fully understand the potential impact that these errors might have on the estimates from analyses that makes use of this data, although evidence from other fields suggests that this may be at a minimum substantial.

In this project we will use cutting edge statistical models developed in the fields of epidemiology, biostatistics and survey research to estimate and adjust for problems of measurement error present in police recorded crime and crime survey data. Drawing on data from 2011 to 2019 we will show the extent of systematic bias and random error in these two data sources, and how these errors may have evolved over time. Once the examination of the presence of measurement error in crime data is completed, we will use our findings to generate adjusted counts of crime across England and Wales, providing a unique picture of how different crimes vary across space and time. Finally, we will use these new crime estimates in tandem with 'off the shelf' measurement error adjustment techniques to demonstrate the potential influence that measurement error has on the findings of existing research.

Alongside this rigorous empirical work, we will also engage in a range of capacity building exercises to furnish researchers with the necessary skills to incorporate measurement error adjustments in their own work with crime data.

Who will benefit from this research?
A number of key beneficiaries of this research are expected:
Police forces
Her Majesty's Inspectorate of Constabulary and Fire Service (HMICFS)
College of Policing (CoP)
Office for National Statistics (ONS)
Home Office
Charities/third sector organisations that engage in criminal justice issues
Local authorities that utilise crime data in resource planning

How will they benefit?
This work will contribute to a better understanding of the problems inherent in the measurement of crime, and the most effective ways to combine sources of data to obtain more robust estimates. Key beneficiaries will be able to make use of corrected counts of crime that overcome limitations of police recorded crime and the CSEW. The identification of the prevalence and form of errors in crime figures will also enable HMICFS, CoP and individual forces to pinpoint areas of crime recording where improvements are required. Adjusted counts of crime will be generated that correctly reflect the errors in their estimation, facilitating their use by government researchers, charities and third sector organisations, local authority planners, and members of the media. To facilitate dissemination of our findings and engage as many potential beneficiaries as possible we will produce non-technical summaries of the main findings and infographics quantifying the (corrected) extent of crime across England and Wales. We will also provide all necessary code and short guides for researchers to generate their own robust estimates so that impact can be ensured beyond the end of the grant.

How will we maximise the benefit?
We have already reached out to an initial network of users that we believe are most likely to benefit from this work. This includes N8PRP force representatives, CoP, members of ONS and Kantar public (responsible for CSEW fieldwork). The research team are well placed to further broaden the scope of the stakeholder group following award of the project funds - IBS is part of a HMICFS working group working to improve the use of crime data in planning activities, and JPS has worked closely with West Yorkshire and Cumbria Police forces in two N8PRP funded projects. The Force Performance Manager at West Yorkshire Police has already expressed interest in liaising with the research team to explore the ways findings from this research project could be applied to their work on demand and performance management.

Other means of generating impact include:
A project website outlining our research aims, proposed methodology, and including regular updates on our work. This will also be used to house academic outputs, briefing papers, all code associated with the project, and revised crime estimates.

A plain English final report summarising the main findings from the research for non-technical users. This will be distributed to all stakeholders and will also be made available on our website.

Recognising the growing importance of rapid and collaborative communication avenues online, we will produce a project twitter account outlining the key findings from our measurement error assessment. This will allow us to directly engage with the academic and non-academic statistics community. We also intend to produce a short piece for 'the conversation' highlighting major policy implications of our findings.

We will liaise closely with the media offices at the Universities of Surrey, Leeds and Manchester to generate appropriate press briefings following the completion of major project milestones.

We will produce bitesize training manuals and a one-day training course held at Surrey (Sociology Day Courses) and Manchester (Methods@Manchester).

Finally, we will present our research at major national and international academic conferences, as well as the Crime Statistics User Group meeting. We will also organise a half day event in collaboration with the Royal Statistical Society Social Statistics Group.