Experimental criminology is the use of advanced experimental methods to answer key questions about the causes and responses to crime.  For example:

• How much crime does prison prevent--or cause--for different kinds of offenders?
• Does visible police patrol prevent crime everywhere or just in certain locations? What is the best way for societies to prevent offending from an early age?
• How can murder be prevented among high-risk groups of young men?

Experimental criminology is scientific knowledge about crime and justice often discovered from random assignment of different conditions in large field tests. This method is the preferred way to estimate the average effects of one variable on another, holding all other variables constant While the experimental method is not intended to answer all research questions in criminology, it can be used far more often than most criminologists assume. Opportunities are particularly promising in partnership with criminal justice agencies.

The highest and best use of experimental criminology is to develop and test theoretically coherent ideas about reducing harm from crime, rather than just evaluating existing or even new interventions.  Testing key ideas, in turn, can help to accumulate an integrated body of grounded theory in which experimental evidence plays a crucial role.  When properly executed, randomised field experiments provide the ideal tests of theories about both the prevention and causation of crime.

These and other urgent questions can be answered most clearly by the use of a research design called the randomised controlled trial.  This method takes large samples of people such as those who might have been involved in crimes as victims or offenders.  It can also take numbers of places, such as schools, prisons, police beats or other units of analysis.  It then uses a statistical formula to randomly select a portion of them for one treatment, and (with equal likelihood) another portion to receive a different treatment: one of the treatments is often the current way of addressing a problem and referred to as the Control group. Any difference, on average, in the two groups in their subsequent rates of crime or other dimensions of life that are being measured can then be confidently interpreted as having been caused by the randomly assigned difference in the treatment.  All other differences, on average, between the two groups can usually be ruled out as potential causes of any difference in outcome. 

This presentation by Cambridge University describes one such experiment: Cambridge Ideas Video

Experimental criminology is a rapidly growing field, with increasing influence on public policy decisions.   These reasons alone make it appropriate to locate the world's first Centre for Experimental Criminology at Cambridge University.  For, like experimental medicine, this branch of criminology uses a scientific method that was invented by a Cambridge scholar, Sir Ronald Aylmer Fisher, whose theoretical work on experimental methods revolutionized the study of cause and effect.   Among his many ideas was the central insight that random assignment of a consistent action across some but not all of a large population could "hold constant" the other factors that could affect any subsequent outcomes.

In 1959 Cambridge established the first Institute of Criminology in the English-speaking world, with close links to the UK government and its need for policy-relevant research.  Established in part with funds from the Wolfson Foundation at the request of Home Secretary RA Butler, the Cambridge Institute of Criminology has engaged equally with theoretical and applied questions of the causes and prevention of crime throughout its distinguished history.  These questions were of great interest to the Institute's founder, Sir Leon Radzinowicz, as well as to two of the previous Directors: Sir Anthony Bottoms and Professor Friedrich Losel.  They have also been of particular interest to the Institute's polymath of all branches of criminology, Professor David Farrington, who co-founded the Academy of Experimental Criminology in 1998 and served as its President (2001-2004).  The Centre’s current Director, Dr Heather Strang, was also its President (2019-2022).

For these and other reasons, the Jerry Lee Foundation decided in 2006 to assist in the founding of the first university centre devoted solely to the advancement of experimental criminology.  With the Lee Foundation's initial pledge to fund a programme of pre-doctoral and post-doctoral 'Jerry Lee Scholars', the University agreed to have the Jerry Lee Centre of Criminology established in the Law Faculty's Institute of Criminology in 2007. In that same year Lawrence Sherman, the University's 4th Wolfson Professor of Criminology, was appointed the first Director of the Jerry Lee Centre.

This appointment also marked ten years of a continuing collaboration between Lawrence Sherman and the Foundation's President, Jerry Lee, who has championed social science research in business and government for decades.  Their collaboration includes contributions to the founding of the Stockholm Prize in Criminology; the Jerry Lee Center of Criminology and the Department of Criminology at the University of Pennsylvania; the Division of Experimental Criminology of the American Society of Criminology; and other initiatives for advancing the institutional development of criminology.  This includes the largest programme of multiple randomized trials of a single crime prevention strategy ever conducted in experimental criminology, the Jerry Lee Programme of Randomized Controlled Trials in Restorative Justice, a series of 12 field experiments involving over 3,000 crime victims and offenders.

The Jerry Lee Centre for Experimental Criminology at Cambridge has two primary tasks:

• To conduct research, with emphasis upon primary and secondary analyses of randomized controlled experiments in crime and justice.
• To select and train an outstanding cadre of experimental criminologists for the future. 

• US National Academies of Science, Engineering & Medicine on publishes 2022 report chaired by Professor Lawrence Sherman on Evidence to Advance Reform in the Global Security and Justice Sectors, addressing training, the rule of law, combatting corruption and excessive use of force. https://nap.nationalacademies.org/catalog/26782/evidence-to-advance-reform-in-the-global-security-and-justice-sectors
• Research undertaken by Associate Professor Matt Bland demonstrates that just 15-minutes a day on foot patrol reduces serious violence in crime 'hot spots', published in September 2021 and reported in The London TIMES in March 2023.
• Graduate Student Stacey Rothwell and Centre Director Dr Heather Strang lead successful experiment testing rapid video response to offender-absent domestic abuse cases, winning greater trust from victims and more arrests of suspects, published in 2022 https://link.springer.com/article/10.1007/s41887-022-00075-w.
• PhD student Sumit Kumar and Centre Director H. Strang publish 20-year study of racial disparity in London, showing young black men 13 times more likely to be murdered than young white men. See https://link.springer.com/article/10.1007/s41887-022-00084-9
• Professor Lawrence Sherman delivers August Vollmer Lecture to audience of 800 people on “Just Right” policing, published in Criminology & Public Policy 2022 (see https://onlinelibrary.wiley.com/doi/full/10.1111/1745-9133.12578   

• Professor Lawrence Sherman receives the 2020 August Vollmer Award
• Yale Graduate School honors four alumni with Wilbur Cross Medals (Lawrence Sherman) 24 October 2017

The Centre's research programme is currently focused in these major areas:

• The prediction and prevention of serious violence, both in high-crime places and with high-risk offenders. This includes various initiatives with UK police and health agencies, as well as with Philadelphia's Adult Probation and Parole Department. The first paper of this project on forecasting homicide was published by the Journal of the Royal Statistical Society
• A longstanding interest of the Centre is in restorative justice, through the multi-national efforts to follow up 12 different experiments from Australia to the UK. This includes its responsibility for the first Campbell Collaboration's systematic review of the effects of face-to-face restorative justice on crime victims and offenders, published in 2013 and now being updated.
• The most rapidly-growing area is the conduct of field experiments in collaboration with UK police agencies, on a variety of topics including the Birmingham Turning Point Project, led by Centre Fellow Professor Peter Neyroud and supported by Centre members Sumit Kumar and Dr. Sara Valdebenito
• A rising area of research is the prediction and prevention of police misconduct, which is supported by data-sharing with the College of Policing. In the first study of the national Barred List of officers dismissed for gross misconduct, Professor Sherman and Dr. Valdebenito are working with MSt graduate Paul Tomlinson to complete a case-control study of some 6000 UK police officers to identify the most serious risk factors at the time of vetting.

With the objective of training outstanding future experimental criminologists, the Centre has pledged to fund a programme of doctoral studentships at the Institute of Criminology for students who have been admitted to the doctoral programme on a part-time basis.  To be eligible for this funding students will be in employment, most likely in a criminal justice agency, and be eligible to pay home fees.  The studentships will cover annual part-time fees up to a maximum of five years’ study. They will be awarded to applicants who can deliver a high-quality experiment in the context of their employment, for example a randomised controlled trial, where the employer will allow and accommodate study for a PhD.

The many advantages of experimental methods help explain why this branch of criminology is growing rapidly.  Just since 2005, the field has seen its first journal established (Journal of Experimental Criminology), its own separate Division of Experimental Criminology within the American Society of Criminology, and the first University centre dedicated solely to this field: the sponsor of this page, the Jerry Lee Centre for Experimental Criminology at Cambridge University.  All these institutions are dedicated to making the most of the better knowledge experiments can bring.

Yet these advantages depend entirely on the capability of the experimenters to insure success in achieving the many necessary elements of an unbiased comparison.  Many, if not most, randomised field experiments in criminology suffer flaws that could have been avoided with better planning.  The lack of such planning, in turn, may be due to the scant attention paid to field experiments in research methods texts and courses.  Even skilled, senior researchers can make basic mistakes when conducting field experiments, since experiments require a very different set of skills and methods than the normal science of observational criminology.

For further information about experiments in criminology please contact Dr. Heather Strang or any of the Cambridge criminologists cited on this website.  .

For other global institutions in experimental criminology, please click on the following links:

• Division of Experimental Criminology, American Society of Criminology
• Journal of Experimental Criminology
• Academy of Experimental Criminology