Fidelity

Fidelity is truth. In software projects we need to know how much “truth” is
in the plan and how much “fiction” might be in the plan.

We know that the more detailed the wbs, the greater probability that it is
truth, rather than fiction. The exception to this involves documenting
heuristic tasks and estimates in detail in the plan. Only document the
actual tasks representing the real work in detail, rather than fictitious
tasks that will be replaced with real tasks later.

The shorter the time span of a task, the nearer our ability to prove the
fidelity of the estimate.

in order to realize this ability, I also need to measure frequently,p
relative to the mean duration of tasks in the plan. That is, I should
measure every time a few tasks are completed, so that any propensity toward
fiction in the estimates can be observed and biased.

Reaction time breeds agility. The shorter the project, the less time to
adjust. The less time to adjust, the more frequent the measurement must
be. The more frequent the measurement, the smaller the mean task duration
must be.

How you plan determines how quickly you will be able to react as fiction
leaks out of your plan.