This article reviews the available methods for validation of self-report measures by substance users. Some advantages of self-report measures are they are easy to administer to large groups of people in different locations simultaneously; they are relatively inexpensive to produce; can be administered in several ways such as interview by telephone, by computer, or in person; and they allow the respondent to choose to skip items thus protecting respondent's choices concerning what they wish to reveal. Disadvantages include fact that respondents can alter their answers according to personal self-presentation motives, or they can paint a very negative picture in order to obtain treatment or intervention; a researcher's bias or expectations can inappropriately impact on how participants respond; and the way questions are worded can influence how they are answered. Also, questions have been raised about the validity and reliability of self-report measures, including sensitivity and specificity of the assessment method. In addition, the method of test administration is a cause for influence upon how questions are answered, such as computer-assisted self interviews, audio-CASI computer assisted self interviews, and interactive telephone voice recording methods. Other methods of assessment, used independently or as confirmation assessments, are biologic techniques which include urine analysis, hair analysis, and saliva analysis, the latter which has been found to be accurate only with respect to validating recent self-reported smoking. Biologic testing has been found to be far from perfect. Finally, an alternative assessment method which measures the automaticity of attitude activation, or the time it takes for the respondent to activate his or her answer, is described. Alternative assessment methods that combine biologic and self-report methods are recommended for further study by researchers to improve substance use measurement techniques. References