The background and methodology of the study are discussed in greater detail, case study vignettes are presented that exemplify GAL activity, and additional data tables from the analyses are included. The methods examined were: law school clinic, staff attorney, lay volunteer with paid attorney, and unassisted lay volunteer. Two examples of each method were studied at nine sites in six States. Data sources included interviews with judges, State's attorneys, and GAL program directors; child welfare and court records; and case studies of GAL activities derived from network interviews. A total of 245 case records and 16 case networks were used. Data analysis examined GAL activities in each model and evaluated the effectiveness of the GAL in serving the best interests of the child. Effectiveness was gauged in terms of 27 measures in 6 areas of case activity: legal activities, services and placement, timing of judicial action, case plan changes, case goals, and stability of GAL representation. Network data were used to provide additional qualitative data on post-dispositional monitoring, contact with child, time on case, and other case dynamics. 5 tables.