Empirical investigations of cognitive skill acquisition have generally focused on differences between novice and expert operators. The result is a neglect of the intermediate stage of skill acquisition in which operators progress through competence towards expert performance. This study investigated the qualitative and quantitative differences in the cognitive cues generated by competent and expert firefighters. Participants first read a written, firefighting-related decision scenario before listing the cues that they considered relevant in formulating a decision. The results revealed that experts generated significantly more cues than competent operators. Further, the types of cues generated by competent and expert operators differed, with experts reporting significantly more safety-related cues than competent operators. These outcomes suggest that differences exist between the cues that are employed by expert and competent operators during decision-making, and that these differences reflect a qualitative change in information processing that occurs during the transition from competence to expertise.