Interaction matrices showing two act sequences from studies of discussion groups, teacher classroom behavior, speech therapy sessions, and policecivilian telephone calls were analyzed using the information theory statistic to obtain estimates of distributional and sequential predictability. Data from 10 studies were analyzed, and the results showed the relative sequential structure ranging from 3.8 to 29.8 percent. Predictability due to distribution of acts ranged from 3.4 to 41.9 percent. Flow chart diagrams were developed showing the sequence generating processes for discussion groups and classroom interaction. The effects of category system design, interactant roles, task logic, and the number of actors on both sequential and distributional predictability are discussed.