The central promise of experimental criminology is its potential to lower the extraordinarily high incarceration rates in the United States. Imagining the counterfactual scenario of medicine without experiments suggests that major changes would be much slower and less effective without randomized field trials (RFTs). Imagining alternatives to the current high rates of imprisonment suggests eventual discovery of more effective programs for crime prevention without prisons, and without courts. Research advances in the use of moral appeals and other mechanisms of attaining compliance through socialization rather than sanction threat provide a fertile research agenda. Executing that agenda with RFTs would be the shortest path to reducing incarceration rates. Critics of RFTs may accept the research agenda proposed in this article but reject the need to conduct the research with RFTs. For all the reasons cited by blue-ribbon commissions, however, any body of research that is the basis for major policy change must be based on the most reliable experimental methods known to science. This inevitably involves the use of RFTs if at all possible. 36 references