Center for Problem-Oriented Policing

Step 9: Know that opportunity makes the thief

For environmental criminologists, "opportunity makes the thief" is more than just a popular saying; it is the cornerstone of their approach. They believe that if opportunity increases so will crime. To see if you agree, consider the scenario suggested by Gloria Laycock and Nick Tilley of the Jill Dando Institute of Crime Science:

Suppose all situational controls were to be abandoned: no locks, no custom controls, cash left for parking in an open pot for occasional collection, no library check-outs, no baggage screening at airports, no ticket checks at train stations, no traffic lights, etc., would there be no change in the volume of crime and disorder?


If you answer that of course crime and disorder would increase, then you, too, think opportunity is a cause of crime. Incredibly, most criminologists would not agree. They believe that opportunity can only determine when and where crime occurs, not whether it occurs. In their view, whether crime occurs is wholly dependent on offenders' propensities and these propensities collectively determine the volume of crime in society.

In fact, crime levels are as much determined by the opportunities afforded by the physical and social arrangements of society as by the attitudes and dispositions of the population. This is difficult to prove without conducting experiments, but it would be unethical to create new opportunities for burglary or robbery and wait to see what happens. However, experiments have been undertaken with minor transgressions. In the 1920s, researchers gave children the opportunity to cheat on tests, to lie about cheating, and to steal coins from puzzles used. Other researchers have scattered stamped and addressed letters in the streets, some containing money, to see if these were mailed. In a third group of lab experiments, subjects were instructed to "punish" others for disobeying test instructions by delivering severe electric shocks through the test apparatus. (In fact, no shocks were actually delivered).

The results of these experiments support the causal role of opportunity. Most of the subjects, even those who generally resisted temptation, took some opportunities to behave dishonestly or aggressively - opportunities they would not have encountered but for their participation in the studies. But you cannot generalize from these minor transgressions to crimes of robbery or car theft. We, therefore, must turn to some other sources of evidence about the importance of opportunity in causing crime.

Suicide and opportunity.

Suicide is not a crime, but like much crime is generally thought to be deeply motivated. However, there is clear evidence from the U.K. that opportunity plays an important part in suicide. During the 1950s, about half the people who killed themselves in the U.K. used domestic gas, which contained lethal amounts of carbon monoxide (CO). This was known as "putting your head in the gas oven." In the 1960s, gas began to be made from oil instead of coal. The new gas had less CO and the number of gas suicides began to decline. By 1968, only about 20 percent of suicides involved gas. This is when a second change began: manufactured gas was replaced by natural gas from the North Sea. Natural gas contains no CO and is almost impossible to use for suicide. By the mid-1970s, less than 1 percent of suicides in the U.K. used this method.

What is deeply surprising is that suicides did not displace wholesale to other methods. The table shows that between 1958 and 1976 suicides dropped by nearly 30 percent from 5,298 to 3,816. (This was during an economic decline when suicide could have been expected to increase and, indeed, was increasing in other European countries.) People did not turn to other methods because these all had drawbacks. Overdoses are much less lethal than carbon monoxide. Hanging requires more knowledge as well as courage. Not everyone has access to guns, which can result in disfigurement instead of death. On the other hand, domestic gas was readily available in most homes. It was highly lethal and using it was bloodless and painless. It is not surprising it was the preferred method for so long and that when the opportunity to use it was removed, the number of suicides declined.

Suicides in England and Wales 1958-1977

YearTotal SuicidesSuicides by Domestic GasPercent of Total

Source: Mortality Statistics, England and Wales: Causes. London: Her Majesty's Stationery Office, Annual

Murder and opportunity.

Opportunity also plays an important causal role in murder, as shown by a comparison made some years ago of homicide rates in the United States and the U.K. For 1980-84, the period covered by the study, the overall homicide rate in this country was 8.5 times greater than in England and Wales. The gun homicide and handgun homicide rates were, respectively, 63 times and 75 times as great. In the whole of England and Wales in this period (with about 50 million people), only 57 handgun murders occurred. In the United States, with a population of about 230 million (less than five times greater) a total of 46,553 people were murdered with a handgun.

These findings tended to be dismissed because the overall crime rate in the U.S. was generally higher than it was in England and Wales during that period. However, in the past 15 years the overall crime rates of the two countries have converged so that there is now little difference between them, with the glaring exception of homicide. There is still a much higher rate of murder in this country because far more people here own guns, especially handguns, than in the U.K. Even the police in the U.K. do not routinely carry guns! So, when people fight here, someone is much more likely to get shot than in the U.K. Similar, but not such striking findings, emerge from comparing murder rates in the U.S. and Canada (see box). Taken together, these comparisons show that gun availability (an opportunity variable) plays an important causal role in murder.

Understanding the arguments in this section, and accepting that opportunity causes crime, does not mean you must deny the importance of other causes, such as inherited personalities, broken homes, and inconsistent discipline. But there is little you can do to change people's personalities or the divorce rate or poor parenting. However, you can alter the criminogenic situations in which they find themselves. Understanding that opportunity makes the thief will help direct your attention to practical means of preventing crime, and help you defend them from criticism.

Next Step

Guns and Homicide in the United States and Canada

A classic study compared the rate of homicides and assaults in Seattle (U.S.A.) and Vancouver (Canada) from 1980-1986 to determine the effect of handgun availability on the crime rate. Although similar to Seattle in many ways, Vancouver has a more restrictive approach to handgun possession. The study found that wider availability of handguns increases the rate of homicide. The key findings were:

  1. The two cities differed little in their rate of assaults.
  2. The murder risk was significantly higher in Seattle than in Vancouver, mainly due to a five times greater risk of being murdered with a handgun in Seattle.
  3. Rates of non-gun homicides differed little between the two cities.

Source: Sloan, John and colleagues (1988). "Handgun Regulations, Crime, Assaults, and Homicide." The New England Journal of Medicine, 319: 1256-1262.

Read More

  • Felson, Marcus and Ronald Clarke (1998). Opportunity Makes the Thief. Police Research Series, Paper 98. London: Home Office