Although scholarly research on the hookup phenomenon has begun to emerge, two fundamental questions remain unanswered: How common are hookups? The current research addressed these two important questions. Confidence in prior estimates of the prevalence of hookups is undermined by the use of imprecise definitions of hookup partnerships and behaviors. Hookup behaviors have also not been defined precisely e. Using investigator-generated definitions for hookup does not resolve this methodological challenge because students may disregard this definition and answer questions with their own personal understanding of the term. Therefore, to address these concerns in the current study, we did not use the term hookup when assessing prevalence. Instead, we defined a casual partner in such a manner that captured the essence of hooking up cf.