Day fines are based on a logical method of determining the amount of financial punishment to be imposed in a particular case and on a specific offender. Judges first establish how severe an offender's punishment should be. This is then broken down into "units of punishment," each equal to a day's pay for the offender, from which is derived the term "day fines." The introduction to the assessment of the two day-fine projects notes that whether or not a day- fine system is, on balance, to be preferred depends in large part upon its effect on court operations and on the offenders themselves, especially their willingness to comply with their legal obligations to pay. The two experiments reported in this study do not provide a definitive test of the concept, but they do begin to provide answers to several of the most important questions. These questions involve whether or not day fines are feasible, whether or not the collection rate improved, whether they have a stronger crime-control effect, and whether there are other significant social costs incurred by the use of day fines. The assessment of the Staten Island day-fine project concludes that although the final outcome of the collection effort is still unknown, the current high level of fines paid and revenues collected demonstrates that at least the introduction of day fines has not diminished the court's capacity to impose fines with confidence that offenders so sanctioned will comply and that cases of default will present no great difficulty for the court or strain available correctional resources. The Assessment of the Milwaukee day-fine experiment indicates that implementation of a day-fine system in a municipal court has the potential to increase collection rates and reduce the cost associated with nonpayment of fines. 15 tables, notes, and appended forms and work sheets used in the two projects