The validity and reliability of self-reported data from heroin addicts: mailed questionnaires compared with face-to-face interviews.

Immediately following receipt of their 1-year follow-up mailed questionnaire, 55 former patients from an addiction treatment program were interviewed personally, and a urine sample was collected. Results indicate a high degree of correspondence of self-reported drug use with the urinalysis reports, and moderately high correspondence between the information on employment, school attendance, legal status,and length of heroin run given in the mailed questionnaire with that provided in the personal interview.