A comparison of various countries' prison statistics is a difficult task. The prison population and changes in it result from complex processes that are affected by the frequency and seriousness of offense, police efficiency, the strictness of the law, and the way judges carry it out, as well as by the modes of carrying out sentences (stay of sentence, amnesty, release on parole, mandatory minimum sentences, etc.). In the United States, 22.3 percent of inmates in prison on January 1, 1996, were serving a sentence of 20 years or more; the average length of sentence for inmates admitted in 1993 was 75.6 months (6 years and 4 months), and the average length of time served by inmates released in 1993 was 26.0 months. By comparison, in Europe the average length of imprisonment varied between 11.4 months in Portugal and 1.1 months in Denmark; Finland's average length was 5.1 months. Further, the number of persons sentenced to an unsuspended prison term per 100 convicted was much higher in the United States than in the European countries. There is no doubt that the American criminal justice system is much more punitive than the European systems. Even allowing for differences in crime rates, sentencing severity is much higher in the United States than in Europe. Young and Brown argue that the pressures within the criminal justice system itself or within the wider socioeconomic and political structure are more important in explaining prison trends than are criminal justice policies. According to them, attitudes toward punishment are driven by a range of cultural factors that are deeply rooted in a society's history, values, and socioeconomic structure. Sentence length is a key variable in understanding relative rates of incarceration, so the reduction in the incarceration rate requires reducing long-term imprisonment. This could be achieved by an extension of parole release, partly suspended sentences, a change in the attitudes and punitiveness of judges, and by a general reduction in the terms of imprisonment imposed. 87 references, 94 notes, 3 tables, and 12 figures