The validity of self-reported cost events by substance abusers. Limits, liabilities, and future directions.

The following review considers data on the validity of self-reports in addict populations, and then it discusses (a) the types of cost-related questions and the assumptions underlying them that are useful to the evaluation of addictions treatment, (b) both internal and external sources of invalidity, (c) the limits on cost-related information that is gathered from administrative databases, (d) methods for assessing measure validity, and (e) the means for improving the validity of self-reports of cost events. With some important exceptions, addicts provide valid data about both medical and criminal cost events. Skilled socioeconomic researchers able to monetarize these events should be able to produce significant cost of illness, cost offset, cost-benefit, and cost-effectiveness research using self-report data.