Lessons learned about DMC and how to reduce it are presented: (1) DMC can exist at all contact points of the juvenile justice system; (2) multiple factors contribute to DMC at different points in the justice system which calls for multi-faceted interventions; (3) DMC intervention strategies need to be data driven; (4) DMC reduction requires support from the top; (5) DMC reduction needs to happen at the local level; (6) DMC reduction requires strong collaborative partnerships; (7) DMC reduction requires sustained efforts; and (8) evidence-based DMC reduction efforts are scarce. Chapter 1 reviews a new method, the Relative Rate Index (RRI) method, to calculate and analyze DMC. RRI involves a comparison of the relative rate of activity for each major stage of the juvenile justice system for minority youth with the rate of that same activity for White youth. The comparison results in a single index number that indicates the extent of DMC in a locality. Chapter 2 focuses on the assessment stage, which involves an in-depth examination of how DMC occurs. A 4-stage investigative assessment process is recommended and described. Chapter 3 explores the preparation process prior to implementing a local DMC reduction effort. Preparations involve the establishment of partnerships with key local stakeholders and the identification of available data and research on the local DMC problem. Once the initial assessment has been conducted and preparations have been made, jurisdictions must select and implement an intervention strategy to reduce DMC. Chapter 4 guides local jurisdictions in the development of initiatives to reduce DMC by providing guidelines for choosing intervention strategies and developing an intervention plan. Chapter 5 provides guidance for evaluating DMC reduction initiatives while chapter 6 underscores the importance of strong partnerships at all levels of government to the success of DMC reduction initiatives. Figures, endnotes, references, appendixes