Find 'em, catch em', put 'em in prison: how to reduce the crime rate

However, the political environment surrounding 'law and order', including penal policy, has changed since the 1980s. In New South Wales, for example, the former Prison Minister, Michael Yabsley, adopted a tough position through the Sentencing Act of 1989 and the NSW Labor Party responded with its own law and order campaign in 1995. Both major parties have been promising tougher penalties for crime in the lead-up to the March 2003 State election, and this pattern is being repeated in other states. The result is that the number of prisoners has increased from 6.1 per 10,000 persons in 1985 to 10.93 per 10,000 persons in 2001.

Imprisonment rates per head of population and per crime committed

While Australia's imprisonment rate per head of population has been growing, the size of the prison population has lagged far behind the growth in the rate of reported crime. In the mid-1960s, Australia locked up approximately 120 people for every 1,000 serious crimes that were committed, but by the 1980s, this figure had fallen to fewer than 30, and it has stayed around this level ever since. Between 1964 and 1986, when the number of serious crimes per head of population increased from 596 to 2,553 per 100,000, the number of prisoners per 100,000 population actually decreased, from 72 to 69.

This is in marked contrast to the pattern in the US where, from the 1980s onwards, both the imprisonment rate per head of population and the imprisonment rate per crime committed increased substantially. This shift in penal policy matches a dramatic change in the crime rate. Thus, we see the crime rate climbing until the 1980s, then flattening following the stabilisation of the imprisonment rate, then falling through the 1990s following the increased rate of imprisonment from the 1980s onwards.

In New Zealand and for England and Wales, the crime rate increased inexorably well into the 1990s, and then began to fall. Imprisonment per crime fell consistently in both countries until the late 1980s/early 1990s, since when it has been rising.

Alternative explanations

The association between crime and the probability of imprisonment seems to vary fairly consistently across the four different countries we have looked at. This seems to lend considerable credence to Murray's belief that the reduced probability of going to prison went hand-in-hand in all cases with an increase in criminal activity, and that tougher penal policies (particularly in the US, and latterly in New Zealand and England and Wales) were associated with a reversal of this trend.

However, while the statistics we have examined look consistent with Murray's hypothesis that 'prison works', they do not prove him right. Is it possible that some factor or set of factors other than the declining use of imprisonment might have been responsible for the shifts in crime rates in the countries we have been considering?
The economic theory of crime discussed earlier emphasises both the severity of punishment and the risk of getting caught. Indeed, Gary Becker believes that the latter may weigh more heavily in most people's calculations than the former. We have seen what happened to imprisonment rates over the last 40 years, but what happened to clear-up and conviction rates?

In his research on Britain, Murray reported that not only the use of imprisonment but also the success of the police in solving crimes, and of prosecutors in securing guilty verdicts, declined relative to the number of crimes being committed from the 1960s onwards. This means that not just imprisonment rates, but clear-up rates and conviction rates were all falling at the same time as the crime rate was rising.

It seems a similar pattern occurred in Australia. Success in clearing up crimes also lagged badly behind the number of crimes being committed during this period. The absolute number of crimes cleared up by the police doubled (from 183 to 364 per 100,000 population), but relative to the number of crimes taking place, it halved. This in turn reflects trends in the number of police officers since the 1960s, for while absolute numbers of police relative to the population increased, the number of police relative to the number of crimes has fallen dramatically - from 194 officers per 1,000 serious crimes in 1963 to 54 officers per 1,000 serious crimes in 2000.
Putting all this together, the probability of going to jail if you committed a serious offence in Australia fell from roughly 1 in 8 in 1964 to 1 in 37 in 1986. This was partly due to a growing disinclination to lock up convicted offenders, and partly to the decreasing ability of the police to clear up crimes. The risk of getting caught more than halved in Australia between 1964 and 1986, and once apprehended, the risk of going to jail then halved again. It is likely that both trends played a part in enabling the growth in crime. This being the case, it is not only prison that 'works', but detection and conviction too.

Conclusion

The evidence reviewed here is consistent with Charles Murray's view that a weakening in the willingness to use prison as a punishment has been strongly associated with an explosion of crime rates. All the countries we have reviewed saw their crime rates rise dramatically as they eased off on imprisonment. Those countries (notably the US) that subsequently increased their use of imprisonment have seen their postwar rise in crime rates stopped, and then reversed. In Australia, where use of prison has not been increased to the same extent, the crime rate has not been curbed with the same success. While not proving Murray's thesis, these patterns are certainly consistent with it. Whether by taking offenders out of circulation, or by deterring people from committing crimes in the first place, the evidence does seem to support the view that prison works.

But this is not the whole story. The economic theory of crime suggests that the risk of getting caught is likely to be as, or more, important in deterring crime as the anticipated severity of the punishment. In Australia, it does seem that the spiralling crime rates of the 1970s and 1980s had as much to do with declining detection and conviction as with declining use of imprisonment. This suggests that penal policy is an important element in the fight against crime, but it is only part of the solution. As economists have been telling us for more than 30 years now, increasing the probability of getting caught appears no less important than increasing the severity of the punishment that follows.