Journal of Consulting and Clinical Psychology 1979, Vol. 47, No. 1, 106-112 Comparison of Alcoholics' Self-Reports of Drinking Behavior With Reports of Collateral Informants Stephen A. Maisto Vanderbilt University Linda C. Sobell Dede Wallace Center Nashville, Tennessee and Vanderbilt University Mark B. Sobell Vanderbilt University Six-month posthospitalization follow-up data were collected from 52 alcoholic subjects and their collateral informants. Subjects' self-reports and collateral reports of subjects' drinking were highly correlated when subjects had been either mostly abstinent or mostly drunk throughout the follow-up period. When subject and collateral reports differed, there was no systematic direc- tion of difference in number of abstinent days, but subjects reported fewer drunk days and more limited-drinking, hospitalization, and jail days than did their collaterals. Number of days that collaterals were in contact with subjects during the follow-up period was not strongly related to the amount of discrepancy between subject and collateral reports. These findings suggest that (a) alcoholics who have been hospitalized for detoxification generally provide reliable self-reports of their posttreatment drinking behavior, and (b) gathering data from collateral informants is an effective method for corroborating alcoholics' self-reports of drinking behavior. With rare exception, studies evaluating alcohol treatment programs have relied on clients' self-reports as a major source of data. Recently, however, the validity of such reports has been seriously questioned. Sobell (1976) reviewed the literature and con- cluded that the reliability and validity of alcoholics' self-reports has not been ade- quately investigated. In fact, what research has been performed has raised more ques- tions than it has answered. Consequently, additional research investigating this topic is needed, along with the development of alternative ways of evaluating alcoholics' self-reports of drinking behavior. The data in this report were collected while Mark Sobell and Linda Sobell were employed at the Orange County, California, Department of Mental Health Alcoholism Services. Preparation of this article was facilitated by Grant No. 5 T32 AA07072, from the National Institute on Alcohol Abuse and Alcoholism. Requests for reprints should be sent to any of the authors at the Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240. Evidence from a series of studies (Sobell, 1976; Sobell & Sobell, 1975; Sobell, Sobell, & Samuels, 1974; Sobell & Sobell, Note 1) indicates that alcoholics' reports of informa- tion that can be verified against official rec- ords (e.g., arrests and hospitalizations) are generally valid. Unfortunately, official rec- ords do not document daily drinking be- havior. Tn order to verify alcoholics' self- reports of daily drinking behavior, some in- vestigators have started using in-field breath tests on a probe-day basis (Miller, 1975; Sobell & Sobell, 1975; Sobell, Sobell, & VanderSpek, Note 2). Several investigators (Miller, 1975; Sobell, 1978; Pomerleau, Pertschuk, Adkins, & Brady, Note 3) have also suggested using liver function tests to evaluate subjects' reports of recent drinking episodes. Another way of verifying alcoholics' self- reports of drinking is to obtain similar information from others (collateral infor- mants) who have had frequent contact with the subjects. In this regard, congruence be- Copyright 1979 by the American Psychological Association, Inc. 0022-006X/79/4701-0106$00.7S 106