Results support the rejection of the hypothesis that prison is an economically efficient means of reducing reoffending in the United Kingdom; a number of sentencing options are more effective and more efficient than standard prison sentences, including community-based sentences and enhancements to standard prison sentences. The analysis suggests that a number of community-based interventions reduce reoffending when compared with standard prison sentences, including residential drug treatment, surveillance, and surveillance with drug treatment. These interventions produce cost savings when compared with standard prison interventions. Additionally, the analysis suggests that there are a number of enhanced prison sentences that both reduce reoffending and save public sector and social costs when compared with standard prison sentences. These include: educational and vocational interventions, sex offender treatment, offender behavior interventions, and drug treatment. The methodology comprised both the rapid assessment of an effectiveness study which identified the change in reoffending resulting from moving an offender from a standard prison sentence to an alternative sentence, and an economic analysis to transform the data on change in reoffending into an estimate of the economic efficiency of moving an offender from a standard prison sentence to an alternative sentence. Tables, figures, and references