Assessment of treatment outcome.
Treatment outcome research consists of two types: controlled clinical trials and in-house program evaluations. Controlled clinical trials are experimental studies designed to test whether or not a treatment is efficacious. In-house program evaluations provide information about the results (outcome) of an individual treatment program. The key components of clinical trials include control groups; randomization procedures; enumeration of those who were screened for inclusion in, those accepted into, and those excluded from the study; a description of the relevant patient characteristics of the sample studied; "double-blinding" for pharmacological studies; raters of treatment effects who are not the therapists for verbal therapies; objective measures of treatment response; follow-up of at least 70% of the original sample; and appropriate statistical analysis of the data collected. In-house program evaluations rarely have control groups or employ randomization. However, a description of the type of patients treated by the program, independent raters, and adequate follow-up of those entering treatment are essential for program evaluation; and the credibility of program evaluation would be enhanced by the use of objective measures of treatment response.