A large number of studies of family and marital conflictual interaction purport to describe relational processes, yet close examination reveals a scarcity of process analyses. Many studies are interactional or systemic in name only. Three basic criteria are proposed as necessary for the development of a systems methodology: observable, sequential, system-level behavioral descriptions. A methodological review of the literature reveals that the first criterion yielded the most abundant set of methodologies. Application of the second criterion resulted in a much smaller number, which after the third criterion dwindled to a mere handful. This review does not focus on the substantive results of these investigations but rather on the research criteria, strategies, and issues that need to be addressed if process-oriented measures are to be developed for the study of interpersonal systems.