Civitas — an English “Institute for the Study of Civil Society” — looks at Crime in England and Wales, which has risen tremendously over the years:
The number of recorded crimes per 100,000 population in 1950 was 1,053 and in 1960 still only 1,610. By 1992 the figure reached 10,943. The latest figure for 2004/05 is 10,537, well over ten times the rate in the 1950s. [...] Contact crime, defined as robbery, sexual assault, and assault with force, was second highest in England and Wales (3.6% of those surveyed). The highest figure was for Australia, where it was 4.1%. The figure for the USA was 1.9% and for Japan, 0.4%.
Although crime is way up in the long term, it’s down in the short term, from a peak in the mid-1990s:
Why has crime fallen since then? The main reason is that more offenders are in prison. To claim that increasing the use of prison reduces crime is controversial. Between 1993 and 2001 the average number of people in prison rose from 45,633 to 66,300, an increase of over 45%.What happened to crime over this period? According to the BCS crime fell from 19.1 million in 1995 to 12.6 million in 2001/02. Was it just a coincidence?
Even if no deterrent effect is assumed, the incapacitation effect of imprisoning on average another 20,000 criminals would have been substantial. How can we work out the incapacitation effect? The Home Office report, Making Punishments Work, estimated that the average offender carried out 140 offences per year.
We can make a rough calculation of the incapacitation effect of jailing 20,000 full-year equivalent offenders. If each prisoner carried out the average number of offences identified by the Home Office, then 2.8 million offences against the public would have been prevented by 12 months in jail.