The software company 37signals, maker of Basecamp, publishes its working method as a book, Shape Up, by Ryan Singer, free to read online. Its rule is “fixed time, variable scope.” Teams work in six-week cycles, and a project gets at most six weeks. “Six weeks is long enough to finish something meaningful and short enough to feel the deadline from the beginning.”
When the work does not fit, the team cuts scope, not time. “Shipping on time means shipping something imperfect.” A project that does not ship in the time set for it “doesn’t get an extension” by default.