The purpose of the context diagram

- Have you ever been in a situation where you've had to make a decision quickly or had someone call to you from in another room and ask you a question like, "Can we make the change now?" What is it that they want to change and why? Before you can answer this seemingly simple question, you need to ensure you understand the context. The same is true if you need to analyze a business unit or an organization. Before you can delve into the detail of what an organization does, or more importantly, make or suggest changes, you first need to understand where and how the organization fits into the big picture of things. The context diagram provides a visual view of how the organization fits within the outside world and is viewed at the highest level. In a way it becomes the checklist for future analysis as each component can be analyzed by drilling down into other detail. The context diagram is the perfect at-a-glance tool to show where the organization fits in the greater scheme of things. Every organization interacts with external entities. These external entities are represented by the boxes in the diagram. They may include the customer, suppliers, banks, contractors, and so on. They're essentially any external entity, the organization shares a relationship with. These relationships are shown by the interactions coming into or from the organization. In the example, we see that the customer places a purchase order against the organization. The organization sends the products and invoice back to the customer. And the customer then makes payment to the organization. The organization deposits the money into the bank and so on. A context diagram is a tool that can be used in a number of situations. It's a great way to understand the relationship the organization has between the various external entities. This high level knowledge enables you to identify any significant impacts that a change through an organization may have and the way they interact with the outside world. By providing context around how the organization interacts externally, you can then start to build an understanding of the functions required within the organization to support these interactions. Another great use for a context diagram is when explaining the scope of a project and how it fits in within the organization. Let's say you're working on a billing system. A system context diagram can communicate to your stakeholders how the new system will interact with the various internal business units and external business partners, if any. When using this tool to communicate to key stakeholders, they can quickly identify the relationships that need to change. These changes become the scope and analysis of what needs to be performed as part of the project. If you're someone new to the organization, creating a context diagram is a great way for you to quickly gain an understanding of the organization and how it interacts. In fact, it's a great starting point with any analysis you need to do. Context diagrams are wonderful visual modeling techniques that provide the overall view of the area in which you'll be interacting with and how it all fits together. So next time you're asked a simple question on whether or not you can make the change, creating and understanding the context will enable you to make a better and more informed decision.