After utilizing 3 measures of suspicion taken from a large traffic stop dataset (n=66,000) in Miami-Dade County, FL, it was verified that police were significantly more suspicious of men than of women in traffic-stop encounters. Specifically, suspect gender was strongly correlated with the decision by officers to complete a field interview card or to request a record check of the driver or his vehicle. In addition, it was found that suspicion was strongly associated with the decision to arrest and that it had a modest, satisfying affect on gender and arrest. Overall, the theory of differential suspicion was supported. The theory of differential suspicion suggests that police may develop suspicion scripts based on repeated criminal contacts with particular subgroup populations. As a result, police are likely to be suspicious of groups who they repeatedly encounter in street-level situations involving crime. In an initial testing of the theory of differential suspicion, this study used gender as the principal variable of interest. References