This article examined the communication participation styles of how one commits to communication, and postulated the COMPASS which measures these styles. The tendency of participants' acts in small group communications in daily life was investigated, and the communication participation style, consisting of four factors - conversation management, active participation, passive participation, and negative participation - was extracted. Active and passive participation are basic styles in communication in relation to assertiveness and responsiveness. Conversation management is related to meta-conversation which manipulates conversation development. Negative participation is a useful factor distinguishing the listeners and spectators. These participation styles showed a significant relation to individual attributes.