Program management is now an important and practical method to deal with multiple related software development projects. A software development program can generate the benefits that cannot be achieved by managing projects individually and it also has the special characteristics such as complexity, uncertainty and interdependence. This dissertation is designed to examine the moderating effect of external communication activities of the program team used on the relationship between goal interdependence and the extent of expertise adequacy. Based upon organizational Information Processing Theory (IPT), theoretical frameworks are developed. The proposed research models are tested by surveying software product development programs across a range of industries with 303 responses. The results will contribute to the understanding of multiple-project communication in a program’s context. The specific interactions between interdependence and communication and the product development coordination will provide a guideline for the industrial practices.