The Outside World

On the surface, the context diagram shows the work area to be studied and its informational connections to the outside world. However, this diagram bears much closer examination, particularly in the area of the adjacent systems. As noted earlier, the adjacent systems are those parts of the world that have connections to the work and have an important effect on it.

Adjacent systems behave like any other systems: They contain processes and consume and/or produce data. We are interested in them because they are often customers for the information or services provided by our work, or because they supply information needed by our work. You can see these relationships by looking at the connections established in the context diagram. It is through these informational connections that the adjacent systems influence the work.

The farther away from the anticipated automated system you look, the more useful and innovative your product is likely to be.

To find the adjacent systems, you sometimes have to venture outside your own organization. Go to the customers for your organization's products or services. Go to the outside systems that supply information or services to your work. Go to the other departments that have connections to the work. Use the guideline that the farther away from the anticipated automated system you look, the more useful and innovative your product is likely to be.

Do not be limited by what you think might be the limits of a computer system. Instead, try to find the farthest practical extent of any influence on the work.

You will usually find that your work is also closely connected to one or more computer systems, often within your own organization, or that you are making an enhancement to an existing computer system. In this case, the computer systems, or the parts that you are not changing, are adjacent systems. The interfaces between your work and the existing computer systems are critical. Although they may prove difficult to describe, you can never know the extent of your work, and eventually your product, if you do not define these interfaces clearly.

Think of it this way: The adjacent systems are the reason that the work exists; they are customers for the services produced by the work. The work produces these services either on demand or at prearranged times. When it does so, the work is responding to a business event.