The Contact Action Space (CAS) of an individual, or group of individuals, has a significant impact on the location of activities and the organization of the use of space. Beginning with the most basic components of a CAS, the individual behavior pattern element is developed, and operational variations affecting alignment and configuration are considered. Five basic measures of a CAS size, density, eccentricity, orientation, and magnitude are calculated and employed to interpret the nature of and changes in a behavior pattern and the associated CAS of a group of 50 individual households during a five year period. The result of the application of CAS analysis to the study of these behavior pattern changes suggest that the concept of contact action space is a useful tool for behavioral studies and has particular application to planning and potential land use research. (Author/RC)