Same as other research, in routine activity theory testing for sexual victimization defining, operationalizing, and measuring theoretical concepts is very important. Because the definition and operationalization of theoretical concepts and the measurement of these as variables are fundamental to the research process, especially when testing the explanatory and predictive powers of any theory. In this paper, the following issues are discussed. First, possible threats to validity and reliability are identified when researchers have attempted to define, operationalization and measure the core concepts of lifestyle-exposure and routine activity theory. Also, how these threats undermine the valid and reliable measurement of these core concepts is explained. Second, threats to validity and reliability inherent in measurement of sexual victimization are identified discussed. Finally, plausible explanations are offered as to how and why these threats to both sexual assault victimization and core concepts influence the statistical testing of the explanatory and predictive powers of routine activity theory.