Factors affecting agreement between alcohol abusers' and their collaterals' reports.

OBJECTIVE: Because of their low cost and ease of use, collaterals' reports are the most frequent source of independent corroboration with alcohol abusers' self-reports of drinking and related events. Although several reviews have shown that we can have confidence in the accuracy of alcohol abusers' reports of their drinking and in the use of collateral reports as an independent validity criterion, neither data source is error free. This study examined factors that influence the level of agreement between collaterals' and alcohol abusers' reports.
METHOD: Using data from a study of natural recoveries from alcohol-related problems, this study examined how agreement between 120 alcohol abusers' (79.2% male) and their collaterals' reports varied as a function of collateral type and of the collaterals' ratings of their confidence in the accuracy of their reports of the subjects' drinking and related behaviors. Collaterals' awareness of nonalcohol-related levels was also examined.
RESULTS: The best agreement occurred for reports from alcohol abusers' spouses who were fairly confident about the information provided. For all variables, some proportion of collaterals respond to demand characteristics of the interview by providing very specific information about subjects' behavior yet admit to being unsure of this information.
CONCLUSIONS: Collaterals who are fairly sure of the information they provide are the preferred informants to corroborate alcohol abusers' reports of drinking and related behaviors. In some cases the best collaterals are spouses who are fairly sue of the information they reported. It is also recommended that treatment outcome studies should accept reports only from collaterals who are confident about the information they report.