A steering committee will organize a public workshop that will feature invited presentations and discussions on options for expanding SAMHSA's behavioral health data collections to include measures of specific mental illness diagnoses with functional impairment. The discussion will explore new measures and efficient mechanisms for collecting the data. Possibilities include adding new measures to existing surveys, initiating new data collections, or implementing model-based estimation procedures that take advantage of existing data sources, in the event that primary data collection methods are cost-prohibitive or not necessary. Survey and questionnaire design tradeoffs, as well as the potential impact of any changes to existing surveys, will also be discussed. An individually authored summary of the presentations and discussions at the workshop will be prepared by a designated rapporteur in accordance with institutional guidelines.