Team cognition has been identified as a key component to achieve mission goals in dynamic, team-based, stressful, distributed and multicultural operations. Effective team performance in complex environments requires that team members hold a shared understanding of the task, their equipment, and their teammates. So, many of the simulation-based training (SBT) systems and programs have been designed (partly) to enhance shared/team cognition. However, these simulation systems lack the sufficient robustness in their performance assessment tools or capabilities (if they have any) to allow for a rich and deep understanding of team cognition. Therefore, the purpose of this article is fourfold: I) to present a brief account of team cognition; 2) to develop the concept of performance diagnosis and present SBT as an approach to the performance diagnosis of team cognition; 3) to present a set of illustrative behavioral markers of team cognition; and 4) to explicate how these elements (performance diagnosis, team cognition, and SBT) can be leveraged to increase training effectiveness through the development of performance profiles--a rich, detailed, and informative set of metrics--and cognitive and behavioral indicators or illustrative markers of team cognition. Research needs are discussed in terms of realizing the potential of this approach in operational and embedded training contexts.