In AIDS research, relatively little attention has been paid to reliability of self-report of drug users. The authors examined the test-retest reliability of the Risk Behavior Assessment (NIDA, 1991) questionnaire. This structured-interview questionnaire was administered twice to 196 drug users in 5 cities over a 48-hr period. Findings indicated that respondents consistently self-report drug use, injection practices, and sexual behaviors; discrepancies do not appear to reflect systematic decreases or increases in self-report; unreliability is associated with poorly worded questions and respondent characteristics; and discrepant reports warrant attention in analysis and interpretation of data. Measurement error has implications for estimating risks, understanding relationships between behavior and HIV transmission, and interpreting change after interventions. Items with low reliability have been revised, and further reliability studies are examining whether revisions have led to improved reliability.During the first decade of the AIDS epidemic, many researchers have relied on interviewer-

Past studies have used various methods to assess perceived risk of HIV infection; however, few have included multiple items covering different dimensions of risk perception or have examined the characteristics of individual items. This study describes the use of Item Response Theory (IRT) to develop a short measure of perceived risk of HIV infection scale (PRHS). An item pool was administered by trained interviewers to 771 participants. Participants also completed the risk behavior assessment (RBA) which includes items measuring risky sexual behaviors, and 652 participants completed HIV testing. The final measure consisted of 8 items, including items assessing likelihood estimates, intuitive judgments and salience of risk. Higher scores on the PRHS were positively associated with a greater number of sex partners, episodes of unprotected sex and having sex while high. Participants who tested positive for HIV reported higher perceived risk. The PRHS demonstrated good reliability and concurrent criterion-related validity. Compared to single item measures of risk perception, the PRHS is more robust by examining multiple dimensions of perceived risk. Possible uses of the measure and directions for future research are discussed.

This study examined the reliability and validity of the Risk Behavior Assessment, a structured interview questionnaire designed to evaluate drug use and sexual HIV risk behaviors. Participants were 218 drug users currently not in treatment who completed the RBA two times over a 48-hour period and gave urine samples on both occasions. We examined internal consistency and test-retest reliability and found that, overall, drug users reliably report drug use and sexual behavior, although the reliability of reports of specific needle practice and sexual behavior items was somewhat lower. Validity results indicated that drug users' accurately report use of cocaine and opiates. These findings indicate that this self-report questionnaire, when administered by trained interviewers, reliably measures HIV risk behaviors in a drug-using population and provides a valid assessment of recent drug use.

Few studies have investigated the optimal length of recall period for self-report of sex and drug-use behaviors. This meta-analysis of 28 studies examined the test-retest reliability of three commonly used recall periods: 1, 3, and 6 months. All three recall periods demonstrated acceptable test-retest reliability, with the exception of recall of needle sharing behaviors and 6-months recall of some sex behaviors. For most sex behaviors, a recall period of 3 months was found to produce the most reliable data; however, 6 months was best for recalling number of sex partners. Overall, shorter periods were found to be more reliable for recall of drug-use behaviors, though the most reliable length of recall period varied for different types of drugs. Implications of the findings and future directions for research are discussed.

Relatively few studies have addressed the psychometric properties of self-report measures of amphetamine use. This study examines the reliability and validity of the Risk Behavior Assessment's (RBA) lifetime and recent amphetamine-use questions. To evaluate validity, 4027 out-of-treatment primarily cocaine and heroin users provided urine samples that were compared to self-report data; to evaluate reliability, 218 completed the RBA at two time points, 48 hours apart. In the overall sample, self-reports demonstrated moderately high validity, with a 95% accuracy rate (kappa =.54). When analysis was restricted to recent amphetamine users validity was slightly lower (71.5% accuracy; kappa = .41). Test-retest data indicated good reliability for self-reports of ever having used amphetamine (kappa =.79), and amphetamine use in the past 30 days (.75 < r < .91). Out-of-treatment drug users provided accurate self-reports of amphetamine use. Reliable and valid measures are essential for describing and predicting trends in amphetamine use, evaluating the effectiveness of interventions, and developing policies and programs.