Generally, the perspective of developmental psychology examines the soundness of age-based legal policies in the context of scientific research and theory on psychological development. It asks whether the distinctions drawn between people of different ages under the law are sensible, given what is known about age differences in legally relevant aspects of intellectual, emotional, or social functioning. This chapter addresses the evidence on the development of legally relevant competencies, capacities, and capabilities. It considers whether transferring juveniles to the adult criminal justice system does in fact make for more effective deterrence, community safety, or public confidence in the fairness of the legal system. Further, it asks whether these goals are more worthwhile than preserving the legal distinction between juveniles and adults because of differences in their developmental status. The framework proposed by the authors argues against transfer policies that are solely offense-based and recommends a return to offender-based policies that permit the relevant decision makers (e.g., judges, prosecutors, and defense attorneys) to exercise judgment about individual offenders' maturity and eligibility for transfer. This approach would be workable both within a system that uses judicial waiver and one that relies on prosecutorial discretion, so long as retribution is not the sole motivating force behind prosecutors' charging decisions. 27 references and 5 notes