With coordination defined as the management of dependencies, complex engineering projects are well coordinated when teams are aware and able to respond to demands for interaction across product and organization systems. Classic representations of dependence in project management standards and practices emphasize sequence: a single dimensional consequence of dependence. However, underlying mechanisms of dependence which drive remain assumed or hidden, preventing analysis of systemic consequence on scope, quality, schedule, and cost. This paper begins with a review of dependence as viewed commonly in system engineering and project management. Building on our recent work to consider engineering projects as sociotechnical systems, we propose dependence characteristics which more meaningfully capture underlying project activity dynamics. Mechanisms are proposed for dependence which are satisfied by the interplay of demand for interaction and the supply of coordination. Attention allocation and exception handling behaviors in the project organization influence the extent of local satisfaction of dependence. Project architectural characteristics lead to emergent and systemic impacts on cost, schedule, and quality. Our next step in this research is introduced, the instrumentation of teamwork experiments to observe and validate the demand and satisfaction of dependencies by project team during complex project execution.