Crime causes great suffering to victims and their families, but the costs associated with imprisonment can also be considerable. These costs are normally justified by the need to inflict retribution to offenders; to deter others from behaving in a similar way; and to prevent re-offending. The size of the prison population depends on the level of crime, the legislative measures and the efficiency of the enforcement measures.
The indicator shown here considers the total prison population, including pre-trial detainees and remand prisoners, per 100 000 of national population. This information has been collected by the International Centre for Prison Studies since 1992, every 3 years or so. It should be noted that not everyone in prison has been found guilty of a crime, due to the inclusion of those awaiting trial or adjudication.
Imprisonment rates may vary by country according to the extent to which they apply home detention or residential rehabilitation as judicial sanctions. These latter applications of the justice system have some prison-like features, but they do not constitute incarceration in an official institution. Additional comparative information is available from the above source: this includes information on shares (in the total prison population) of pre-trial detainees/remand prisoners, female prisoners, young prisoners, foreign prisoners, and occupancy levels (in percentage) relative to official prison capacity.
Over the last fifteen years, most OECD countries have experienced a continuous rise in their prison population rates. On average, across the 30 OECD countries, this rate has increased from a level of 100 persons per 100 000 unit of the total population in the early 1990s to 140 persons in the late 2000s. The prison population rate is highest in the United-States, where 760 per 100 000 population were in prison in 2008: such level is three to four times higher than the second highest OECD country (Poland), and has increased rapidly.
The increase in the prison population extends to most other OECD countries. Since 1992, the prison population rate has more than doubled in the Netherlands, Mexico, and Turkey, while it declined in Canada, Denmark, Hungary, Korea and Switzerland.
There are large differences across countries in the make-up of the prison population. On average, one in four prisoners is a pre-trial detainee or a remand prisoner, but these two categories account for a much higher share of the prison population in Italy, Luxembourg and Turkey. Women and youths (aged below 18) account, on average, for 5% and 2% of the prison population respectively. A much larger share of prisoners is accounted for by foreigners (22% of all prisoners, on average), with this share exceeding 40% in Luxembourg, Switzerland, as well as Austria, Belgium and Greece. In several countries, the rapid rise in the prison population has stretched beyond the receptive capacity of existing institutions; occupancy levels are above 100% in more than half of OECD countries, and above 125% in Greece, Mexico and Spain.