In Finland in the 1960's, criticism of the treatment ideology merged with another liberal social movement against an outdated and overly severe Criminal Code and the excessive use of custodial sentences. Principles of proportionality and perceived procedural fairness were emphasized as key factors in influencing people's willingness to obey the law. Further, cost-benefit analysis was introduced to criminal political thinking, requiring that in making choices between different strategies and means, the probable policy effects and costs should be carefully assessed. Since the early 1970's, there has been a purposeful movement toward a more lenient system of sanctions, particularly a reduction in the use of custodial sentences. Along with the increase in the number of community services orders as an alternative to prison, the number of unconditional sentences of imprisonment has decreased. The parole system has also proven to be an effective tool in controlling prisoner rates. An examination of prison rates and crime rates shows that crime rates rise and fall according to laws and dynamics of their own, and sentencing policies in turn develop and change according to dynamics of their own; these two factors are independent of one another. Thus, the decrease in the Finnish prison population has resulted from a conscious, long-term, and systematic criminal policy. 7 figures, 2 tables, and 10 references