Mastering the Requirements Process ↑
11.84.1.1 Rabbit Projects vs. Elephant Projects
We are asking the reader to consider his or her project. Is it a small, fast, short-lived project? If so it is a rabbit project and you should do only certain things and omit others. For example, we suggest that rabbit projects should certainly discover all their requirements, but that they do not have to write a comprehensive specification. Rabbit projects can abbreviate their specification.
On the other hand, if you are outsourcing or are working on a military, medical or some government projects, you are an elephant. Elephants are slower and larger and have a need for formal documentation (try getting a new airplane past the FAA without a complete specification).