; (2) develop plans appropriate for a community to address those unmet needs with juvenile delinquency and gang prevention and intervention practices; and (3) implement and evaluate such plans in a manner consistent with this title. 302. Definitions In this title: (1) Administrator The term Administrator means the Administrator of the Office of Juvenile Justice and Delinquency Prevention. (2) Community The term community means a unit of local government or an Indian tribe, or part of such a unit or tribe, as determined by such a unit or tribe for the purpose of applying for a grant under this title. (3) Designated geographic area The term designated geographic area means a 5-digit postal ZIP Code assigned to a geographic area by the United States Postal Service. (4) Evidence-based (A) In general The term evidence-based , when used with respect to a practice relating to juvenile delinquency and criminal street gang activity prevention and intervention, means a practice (including a service, program, activity, intervention, technology, or strategy) for which the Administrator has determined— (i) causal evidence documents a relationship between the practice and its intended outcome, based on measures of the direction and size of a change, and the extent to which a change may be attributed to the practice; and (ii) the use of scientific methods rules out, to the extent possible, alternative explanations for the documented change. (B) Scientific methods For the purposes of subparagraph (A) , the term scientific methods means— (i) evaluation by an experimental trial, in which participants are randomly assigned to participate in the practice that is subject to such trial