Skip to main content
Rebecca Wirfs-Brock’s Blog and Informal Essays wirfs-brock.com

The Value of Design Documentation


Recently I asked students to tell me what kinds of requirements they start with and what (if any) design documents do they produce.Several students said that they produced documentation just because it was part of their development process. As a consequence, they felt that the documents were rarely read, were hard to keep up to date with the real code, and were expensive to generate. I know that everyone isn't free to change their process...but if something is expensive to do and doesn't add value, especially in this economic climate: look for a better, less expensive alternative.

My advice is to keep the precision at a low enough level that you don't have to keep updating it with every small change. Last year I helped one client develop a 2 page high-level view of the architecture for IT applications. On the first page was a component diagram. On the back was a high-level statement of each components' responsibilities. While during development they produced other docs, these high-level overviews were intended to orient people who were going to maintain these applications. They were pleased when this high-level view was well-received by those developers.

Simply because a tool lets you reverse-engineer an implementation into detailed class or sequence diagrams doesn't mean you should create lots of implementation-level diagrams. On another project where we used TogetherJ, we pruned sequence diagrams (to omit detail) so that business analysts could understand the basic flow w/o having to know everything. These edited diagrams didn't end up in any permanent design document. Instead they helped explain our working prototype.

To be effective design documents have to communicate valued information to its intended audience. So if you find yourself creating documents that aren't useful...well, think about suggesting cost cutting and process improvement ideas to your team and management. This is the right economic climate to suggest such positive changes.