Key decisions within the criminal justice system, such as bail, sentencing, and plea bargaining, are a result of the belief on the part of the decisionmakers that they follow policies other than those that actually guide their decisions. Also, they believe that the policies that are followed are often simple ones, involving only a few decision factors, and that the decision outcomes are often assigned to defendants in a reasonable manner but that, even so, the outcomes are often ineffective. Many proposals for the reform of the criminal justice system are based on the testimony of decision makers or 'experts' whose knowledge of the system is often flawed. Therefore, it is unlikely that reforms will have a beneficial impact on criminal behavior until much more is known about day-to-day decisions of judges, prosecutors, and probation officers. (Author abstract modified)