Notation and Usability

It's easy to develop your own notation; all too many people do. It's hard to do it well, and many notations that fill our journals and magazines are not very good as modeling tools.

Designing a good notation is like designing a good user interface. The goal is to reduce human memory load. The Great Law of Usability says a system should be usable—without training, assistance, or manuals—by someone who knows the application but not the software (Constantine 1991b). A really good notation, then, is one that an experienced software engineer who knows how to design and build software can interpret directly and intuitively without a week-long class or a complicated cheat-sheet. You shouldn't have to remember arbitrary things like a double-barred box as a dynamic object or one with a flag in the corner as a reused library component.