Treatment services: triangulation of methods when there is no gold standard.

Information about treatment services can be ascertained in several ways. We examine the level of agreement among data on substance user treatment services collected via multiple methods and respondents in the nationally representative Alcohol and Drug Services Study (ADSS, 1996-1999), and potential reasons for discrepancies. Data were obtained separately from facility director reports, treatment record abstracts, and client interviews. Concordance was generally acceptable across methods and respondents. Although any of these methods should be adequate, additional information is gleaned from multiple sources.