Ideally tracking stories is much better than tracking tasks even at the iteration level since the stories can be proved
to work through the acceptance tests and tasks can't. However, when there are few stories in the iteration, some teams
also use tasks to help them gain a sense of progress.
The tracker simply tracks how many tasks have been done during the iteration and how many are left. This information is
readily available during the stand-up meetings. Half way through the iteration, the team should have done about half
the tasks (in terms of the task cost estimates). If not, it is a sign that the iteration plan needs some tweaking. If
the team is not going as fast as planned, the tweaking may consist of removing one of the stories from the iteration.
If they are going faster than planned, then the team can ask the customer to bring a new story into the iteration. This
is how the team iteration velocity will fluctuate over time.
On a regular basis, the tracker presents the progress the team is making in the iteration. This information can be
presented in the form of a big, visible chart hanging in the team's open workspace. Progress is often presented as the
number of tasks or stories done vs. planned for the iteration.