Sometimes, it’s random factors: on one data-center project, prairie gophers chewed through a power cable, the backup generator failed, a critical test crashed (no joke, it really happened).
Other times, it’s human factors: on its maiden voyage, the flight crew requested fuel in pounds, the ground crew loaded fuel in kilograms, the plane ran out of gas mid-air (the “Gimli glider”).
One defense is uncertainty allowance. Wait for the bad things to happen, and use the allowance to recover.
A second defense is to go looking for the bad things before they strike.
That’s where Earned Schedule fits in.
It acts as a DEW line, detecting and warning of problems early, while there’s time to respond.
- Estimated End Date: as the estimate approaches the planned date, the need for action rises.
- Future Performance Rate: as the index closes on the threshold value (1.1), action must be taken before it’s too late.
- Statistical Analysis: as a trend rises toward the high bound, it calls for a quick response.
Usually, the metrics re-enforce one another and our expectations.
Occasionally, they send mixed signals and undermine our expectations.
When that happens, don’t ignore it. Treat it like the foreshocks that precede an earthquake—a fair warning. |
