Validity of Self-reported NEP Attendance Safaeian et al. PRACTICE OF EPIDEMIOLOGY Validity of Self-reported Needle Exchange Attendance among Injection Drug

Some studies have indicated that needle exchange programs (NEPs) can be effective in reducing drug-related risks for human immunodeficiency virus (HIV) seroconversion; however, others have reported higher HIV incidence rates among NEP attendees. Since many studies rely on self-reports of NEP attendance, the authors investigated the extent to which differential misreporting of NEP attendance could bias risk estimates. Over a 3-year period from 1994 to 1997, self-reports of NEP attendance from participants in a prospective study i