Available statistics on the number of youths living away from home are unreliable because full coverage of all out of home placements is uncertain, there is probably some duplication in figures, and the number of admissions is often estimated. This report describes the major data series associated with the mental health, juvenile corrections, child welfare, and alcohol and drug abuse reporting systems. The author describes recent trends within each system, and identifies types of facilities where the counts seem to have a minimal overlap and those where duplicative counting is most likely to occur. On the basis of these assumptions, the report outlines a combined analysis of recent institutional trends and strategies for creating a national system that can provide an accurate count of facilities and youths. 5 tables and 27 references