The Application to Software Development

When I returned with our refills, Roscoe took a long puff on the stogie and started in again. "It seems to me," he began, "that software development projects tend to have, in general, the following characteristics:

• Resources are very tight; there always seems to be little margin for error.

• The 'target' is hard to get in focus at the outset; just as in horseshoes, we have to get used to our swing and calibrate as we go. Another way to state this is that requirements are usually poorly understood at the beginning.

• Execution errors are unavoidable, especially at the beginning.

• The target always moves during the course of the project.

• Staying on a bad path too long is typically catastrophic; it means throwing out work you thought you'd 'accomplished' and starting over again.

When you take these characteristics into account, an iterative development approach with short vectors starts looking pretty darned important."

The argument was persuasive. It was clear that errors, particularly in early iterations, could have a really big impact unless they were detected and corrected. When I mentioned this to Roscoe, he nodded emphatically.