How Soon a Feeling of Urgency Is Established
The intensity level varies quite dramatically on a twelve-month, non-iterative, waterfall-process project. At the start of the project, when team members feel no stress about the deadline, they may take leisurely two-hour lunches. During the thirteenth month of the planned twelve-month project, they’re already into their second or third month of working nights and weekends. As my colleague Niels Malotaux points out, "As long as the end date of a project is far in the future, we don’t feel any pressure and work leisurely. When the pressure of the finish date becomes tangible, we start working harder."
Even with four-week iterations, the end date is never very far in the future. But it’s sufficiently far away that many teams will feel tangibly less stress during their first week than during the fourth and final week of an iteration. The goal is to select an iteration length that evens out the pressure the team feels. The point is not to put the team under more pressure. ("You will deliver today!") Rather, the point is to take the total amount of stress the team would normally feel and distribute it more evenly across a suitably long iteration.