Article in Science / Social Sciences / Sociology
Criminology has failed to predict and explain the crime drop. Would a new criminological theory of vulnerability offer a better explanation, help to evaluate crime reduction initiatives and help predict future trends in crime?

Postscript 17th May 2011.

The ideas in this article are considerably expanded upon in a later -tongue-in-cheek- article entitled:Before the Crime Forecast that outlines the limitations of what I believe to be currently our best policy oriented explanations for crime, bit offers nothing more than a the foundations of a junk science solution. In this new article I propose an outline for a new theory - Dynamic Vulnerability (DV) theory - that is designed to scientifically forecast crime and provide a universal theory to explain causal influences upon crime rate changes and shifts. By default, if DV theory can accurately predict crime and its explanatory ideas are supported by observation and experiment then it will solve criminology's search for a universal theory of crime - which is, undoubtedly, a fools errand.

Mike Sutton

There has been what criminologist Jock Young has referred to as an unfathomable crime drop (Young 2004) across the western industrialized world.

Some renowned criminologists (Farrell et al 2010) amongst many others, are making a relatively good argument, that I contest in this article in the spirit of scholarly criticism is nevertheless irrational, hugely uninformed and heavily biased, in its attempt to predict the past with a pet theory in order to hypothesize that the 15 year crime drop is due to a decrease in vulnerability of targets due to target hardening - so called 'opportunity reduction related' measures.

In this article I argue that Farrell et al's (2010) attempt to explain the past now is problematic for several reasons: (1) these very same criminologists were strangely unable or at least possibly reluctant to predict the crime drop before or even during much of its occurrence (2) they do not provide us with a base rate for 'normal crime levels' (3) do not predict that crime will continue to fall or that it will stabilize to unknown base rate 'normal levels' (4) do not calculate the probability that they are wrong. and (5) Make the assumption that the reason for crime drops in the future will resemble those in the past (see also Farrell et al 2008).

Why is that so if they are able now to be so wise after the event?

To repeat the point already made, it is in a kindred scholarly spirit of healthy scientific skepticism and criticism that marked The Enlightenment that I wish to know what changed in the work and 'knowledge' of my friends and academic colleagues Farrell et al (2010) other than an only too common human desire to safely explain the past rather than predicting the the future? Too often in criminology, well intentioned healthily skeptical criticism of the type that I hope is contained in this article has been treated at academic conferences and in 'a reply to...' statements as personal attacks, which has led to personal and published animosity. It is as though many criminologists are unaware of the principles of The Enlightenment, which was the beginning of the tradition of healthy scepticism and criticism, and the abandonment of scholarly acceptance of 'knowledge' authorities. But that is another story that could fill an entire article.

Academics are no exception to the general irrationality of others who seek to explain the past. Sutherland (2007. p. 174), for example, explains that we are far more adept at inventing causal explanations for what has happened, rather than what will happen next. After all, he writes: '... explaining the past is not such an exacting task given the multiplicity of possible causes.'

The irrationality of seeking to 'predict the past' with limited evidence, rather than making good guesses at causes and then doing good research to predict the present or future is compounded by the fact that scientists in the physical sciences have long abandoned the notion that scientific theories are obtained by generalizing from repeated experiences along with the 'principle of induction', which is (a) that the future will resemble the past and (b) that this misconception asserts anything about the future (see Popper 1963; Deutsch 2011, p.p. 30-31).

Arguably, a more rational argument is that because crimes are diverse social constructs operating in a complex open social system of interlocking human contingencies, they are at different times, and to different degrees in time, shaped in style and number by diverse factors that are extremely difficult to know during the event never mind after it has happened. Such factors might include legislation, governance, tolerance, prejudice, birth rates, cultural learning in terms of how to deal with crimes and how and why to commit them, efficiencies and other policing and wider criminal justice system impacts, social inequalities, unemployment, the built environment, vulnerabilities of targets (people and their possessions), the varying presence of potential and prolific offenders and targets in the same place or within the same realm of influence (such as online), illegal drug use and its fashions and so called 'epidemics', alcohol consumption, recreational activities (indoors and outdoors), the economy and demand and supply for the targets of theft. Changes in one or two or several of these areas - and perhaps in other unknown areas - may have resulted in a key element or elements impacting on others, or perhaps working together in an unknown combination of forces.

Whatever the cause and mechanism of change behind the crime drop, it might even be understood as an entirely expected regression to the mean effect on the previously high (possibly peak) crime levels.

Just as single causes can cause multiple component failure in complex mechanical and electrical systems - such as happens in nuclear disasters such as the recent one in Fukushima - so too might a single cause be responsible for the crime drop. Or else, it may be the case that a number of mutually dependent causal factors for crime ceased, changed or reduced at the same time.

It shows how little we know about crime that I am unable to decide with confidence, either way, whether it is remarkable that we do not have less or more crime than we do in western industrialized societies. For arguments sake, I will settle on the notion here at least that it is in fact remarkable that we do not have more crime than we do, given the inequalities in society and the disparity between goals and means for large swathes of the population.

If each crime committed, therefore, is in fact a remarkably rare event - given that a wealth of so called ‘opportunities’ for various violent, property and motor vehicle crimes abound daily for most people but are not exploited - then it helps to consider whether the commission of any given crime has just one, or a small cluster, of independent causes or whether its occurrence requires the 'presence' of all of several other events. If any given crime – let us take local domestic burglary as an example - can be caused by any one of a number of relatively small independent probabilities (say by way of just some examples of factors correlated with offending such as: a potential offender's father who has been imprisoned, his history of being a disruptive pupil, living in a high crime area, being aged 15 to 25 and not married, being unemployed, having relatively low impulse control, having criminal siblings and living in an area where homes with stuff worth stealing, because the wider public buy them can be broken into quite easily without detection) then, as Sutherland (2007: p. 171) explains, many small independent probabilities may add up to quite a large probability. If, however, the event of a domestic burglary is determined only by the occurrence of all of several other events then the probability of the event occurring will be much lower than that of any one of those several other events occurring. If that is so then this would explain why burglary is a relatively rare event.

Since, for example, relatively affluent young academic criminologists, whose fathers were not imprisoned, who do not have low impulse control, who are not unemployed, and who do not live in run-down high crime areas, who were not expelled from school, tend not to be domestic burglars even when a wealth of so called opportunities to break in and leave undetected abound on a daily basis, it seems like a good guess that domestic burglary in fact requires the occurrence of several other factors or 'events' than just opportunity. And it is because it depends on several other 'events' occurring that the probability of burglary occurring is lower than the probability of such things as successful 'opportunities' for burglary occurring.

And what exactly is opportunity anyway? My Collins dictionary (1979) defines it as: "(1) a favourable, appropriate or advantageous combination of circumstances (2) a chance or prospect." Given such generally accepted definitions of opportunity, crimes from theft by finding to the most audaciously planned and executed armed bank robbery, indeed every crime that is committed must have had some kind of opportunity - otherwise how else could any of them have occurred?

Crime as 'opportunity' then must be true, which means it is self-evident in that opportunity - post hoc is always there once a crime has been committed. This makes it a truism and, therefore, a very poor explanation for, or predictor of, crime. Because opportunity is used in criminology as a general broad label that merely applies a name to any target that any offender deems - through a process explained in Rational Choice Theory - as worth preying upon and vulnerable enough, rather than as a measurable scale of predictive target vulnerability - opportunity cannot be tested in advance as a theory that it is a causal factor in crime.

The best we can say of opportunity is that it is a necessary but insufficient and very poorly defined condition for crime to occur. No wonder then that proponents of 'opportunity' explanations for crime did not predict the crime drop. And equally we should not wonder why those now seeking to predict the past with such broad and weak explanations cannot do so with any degree of mathematical confidence of the probability that they might be wrong.

In the healthy spirit of scientific criticism, I think that the 'opportunity' explanation for crime is a poor explanation. Because when crime inevitably rises again those who support this explanation can simply shift their explanation - post hoc - with mere biased rhetoric to account for crime by saying that new opportunities have been discovered or stumbled upon by offenders, old and/or new. But opportunity as a cause of crime is not even a good guess because in science good guesses are hard to vary in this way (Deutsch 2011) even before they are tested by experiments and other research. Karl Popper (1963) established this argument and was almost certainly right when he wrote that good theories are those that can be completely falsified by outcomes. Searching for theories to predict the past with 'most likely to be true because they are easy to vary' theories such as opportunity as a cause of crime and opportunity reduction as a cause of crime reduction is a false goal for knowledge.

Failing to accept the fallibility of our own pet theories, seeking out theories that are most likely to be true rather than those that can be falsified, and constantly seeking confirmatory evidence while paying less attention to 'threats to pet theories' is exactly how unscientific fallacies become widely believed and orthodox myths.

Farrell et al confidently predict that improved situational measures - so called 'opportunity reduction' - is the most significant causal factor in explaining the crime drop. But does crime operate in a social bubble? Given the diversity of behaviour that is criminal, the diversity of target types (people and objects), the diversity among offenders, crime might better be understood to be in reality a complex interrelated and ever-evolving adaptive social 'crime system' - which suggests it would be wrong to seek to provide simplistic causal explanations for the past.

I think that a better way forward is to begin studying what a good sample of prolific offenders, and potential offenders, themselves actually do - as they do it live - in the face of, policing, crime reduction measures, sentencing etc. To date, the criminological demand for data has been heavily focused upon heavily flawed and extremely limited official police and crime survey data about offences, offenders and victims. If non-criminologists are aghast that an adequate policy oriented study of how offenders actually deal with attempts to thwart, catch, deter and punish them has never been conducted in real time, they would perhaps be shocked to learn that many (perhaps even most) criminologists have never even conducted face-to-face research with prolific offenders - preferring instead to hide behind statistical analysis, studies of police at work and critical studies of the work of others etc. For my own part, I have personally interviewed over 100 offenders since starting my stolen goods markets research in 1994 - but I have never, I must admit, conducted ethnographic research outside of the relatively safer and much easier to research criminal areas of the internet.

Why assume that 'opportunities' operate independently?

In addition to the five reasons I gave at the start of this paper for why Farrell et al's (2010) paper is problematic I now wish to add a fifth. Namely that it lacks a theory predicting that crimes have significant causal roles (such as vulnerabilities - which go - at least in part - by the name of 'opportunities' in Farrell et al's paper) that impact on crime rates completely independently of other significant causal roles - such as, for example, the international and national demand for supply by theft, (Sutton 1998), which has been recorded in the past in relation to crime rises in jewellery theft, computer chip theft, and scrap metal theft and alternative sources of illicit income such as the production and selling of cannabis or the poorly recorded crime of shoplifting.

The reasons why events such as crime drops or increases in crime happen are difficult to know in advance or as they are happening but they are much easier to guess and it is safer to be wiser about them after the event. By way of example, a much simpler event than crime is the 33 per cent increase in spinach production in Texas USA in 1936 that has been attributed to Popeye. But with what degree of certainty can we possibly attempt know that even a simple cartoon character like Popeye was the cause - or even a cause (Sutton 2011) of farmers producing more spinach once the planting and the harvest is over?

The need for a scientific notion of crime vulnerably reduction is a problem in need of a solution

A better solution to the 'problem' of opportunity as a poor explanation is to substitute this simple woolly rule of thumb notion for one of a scientific scale of vulnerability.

A scientific theory of vulnerability as a causal factor in crime that moves beyond being a simple truism would help to produce a hypothesis that enough measurable vulnerability reduction would cause a general crime drop. To move towards this better explanation for crime and how to reduce it, we would need to (1) formulate some kind of measurement scale of vulnerability that can be understood in terms of resistance to another measurement scale of (a) actual and (b) potential offender motivation and capabilities. To get to that stage, a series of experiments would need to be properly and independently conducted (ideally not solely by those with a pet theoretical axe to grind in favour of situational crime reduction measures) to (i) measure the extent of target (victim) deflection (ii) measure for displacement (iii) measure for diffusion of benefits (halo effect of crime reduction in non-experimental areas) (iv) measure for any reduction in expected offending by potentially new offenders (v) measure for any reduction in offending amongst active offenders (vi) measure the extent to which offenders give up current offending all together. Supporters of 'opportunity factors' frequently claim this has been done with studies such as, for example, Kirkholt and Boggart Hill. But those famous studies, by way of mere examples, are known to be fundamentally flawed by heavy research bias that in the former focused too much on evidence that supported evidence of impact while irrationally playing down any threat to theory. In the case of Boggart Hill - the success of the project may have been in no small part due to police bribing informants with heroin (Sutton 2011).

A criminological theory of vulnerability would be a good explanation for crime and its reduction if it could not be varied even before experiments to test it. Although this should not be an intention in formulating it, such a theory would also be likely to have significant 'reach' (Deutsch 2011) to other areas; for example, such as an evolutionary explanation for why some species and viruses threaten particular organisms. And it might help us also to think about how some vehicles - being stronger and safer - pose a selfish threat to weaker vehicles and their passengers if they collide on the road. Indeed it might help us to better understand the effects of competition as an evolutionary process in all human affairs.

A measurable, and therefore testable, Vulnerability Theory of crime and crime reduction might turn out to be one with unlimited potential to create further knowledge.

Poor crime science leads to general fallacies and myths about crime

Unscientific rhetoric - which has become the accepted norm in much that passes today for orthodox criminology - allows others such as Nottingham's Labour Party to take personal credit for the crime drop in Nottingham. Is the Labour Party claiming credit also for the drop across the entire western world? Or do they think perhaps that Nottingham is an island cut off from the rest of the world? In this respect the Labour party are creating a myth in order to explain something they do not understand in the same way the ancient Greeks chose to delude themselves by inventing the myth of Hades' god of the underworld kidnapping and raping Persephone - which ultimately resulted in Persephone's mother (Demeter) compelling the entire planet Earth to become cold and bleak during Winter. Once the ancient Greeks became aware that the seasons were not the same in different parts of the world at the same time their myth lost its explanatory power. What next myth, I wonder, will the Labour party choose, disingenuously, to invent and then 'believe' once they learn that the crime drop has been the same throughout the Western industrialised modern world?

Conclusion and the way forward

Criminology's failure to predict or rationally explain the crime drop has resulted in the situation where uneducated politicians can make ludicrous claims in order to invent and widely publish the ludicrous myth that they are the ones to receive credit for the crime drop in Nottingham.

Academic criminologists claim to be scholarly experts and so we should expect more from them than credulous, uneducated politicians. While it is probably impossible to take the politics out of criminal justice policy making, such politics needs to be informed, wherever possible, by hard scholarly scientific methods not sloppy fallacies and myths.

It is time that criminologists embraced the need for a crime science that is indeed a true science. Merely calling something crime science does not make it so. The failure of criminology to rationally predict the future, past or present crime drop must become a starting point for change.

I believe that we need to develop a multi-disciplinary approach to understand bad scholarship and bad science in all areas.

Developing a discipline of Dysology would help criminology to develop into a true crime science. What better place to start than with the problems with the notion of crime and opportunity that currently underpins the development of what some pioneers are calling crime science.


Collins Dictionary of the English Language (1979) , London. Collins.

Deutsch, D. (2011) The Beginning of Infinity: Explanations that transform the world. London. Penguin Books.

Farrell, G. Tilley, N. Tselone, A. and Mailley, J. (2010). Explaining and sustaining the crime drop: Clarifying the role of opportunity-related theories . Crime Prevention and Community Safety. 12, 24 – 41

Manifesto (2011) Crime Cut to 30 Year Low in Nottingham. In: Proud of Nottingham: Positive Politics for Nottingham Labour:

Popper,K. (1963) Conjectures and Refutations, London: Routledge and Keagan Paul. See:

Sutherland, S (2007) Irrationality. London. Printer and Martin

Sutton, M. (1998) Handling Stolen Goods and Theft: A Market Reduction Approach. Home Office Research Study 178. Home Office. London.

Sutton, M. (2011) Did Popeye Really Increase Spinach Production and Consumption by 33 per cent in 1936?

Sutton, M. (2011a) The Bad Secret of Boggart Hill.

Sutton, M. (2011b) The Problem of Zombie Cops in Voodoo Criminology: A 27 year old myth about beat patrol policing is busted.

Young, J. (2004) Voodoo Criminology and the Numbers Game. In Ferrell, J. Haywood, K., Morrison, M. and Presdee, M. (eds) Cultural Criminology Unleashed. London. Glasshouse Press. Available online:

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Mike Sutton
Dr Mike Sutton is the author of 'Nullius in Verba: Darwin's greatest secret'.

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