Defining and understanding the processes are steps often taken in parallel with understanding the data. Or the focus on processes will follow closely on an understanding of the data requirements, or vice versa. Whatever the order, systems analysts and designers frequently use tools called process models to develop a clear understanding of system processes and to ensure this information is communicated clearly to key stakeholders in the project. What the information system is expected to do is the primary focus of process models, which can also be thought of as essential models, conceptual models, or business models. Although smaller projects may not merit the creation of actual models, a clear idea of what the system is expected to do will have to be developed and communicated to key stakeholders.

Above is an example of a Context Data Flow Diagram. This diagram can communicate essential information about what the system is expected to accomplish. The diagram indicates “external agents,” who should be thought of as those people or parties interacting with the information system. Also noted are key processes, as indicated by the arrowed lines: these represent what the system is expected to do, as well as the main inputs and outputs the system will be expected to process. The Context DFD provides a snapshot overview of the system, and for this reason, this type of diagram is often something developed in the initial stages of the project. Notice that the diagram does not indicate how the system will perform these processes. The “how” part, which is the complete technical design, will come after the essential features of the system are understood.