John Goodpastuer has a nice post on the logic of Schedule Variance. Anyone using Earned Value should download the DAU Gold Card, fold it and keep it in your pocket. This can be found by Google'ing "Defense Acquisition University Gold Card." Ignore the security certificate warning.
For those of us working programs that require badges, we have a laminated version hanging on our lanyard, along with the accounting calendar, and other "reminders."
There is a notion going around that Schedule Variance can be zero (0), that is SV shows 0, and the project can still be late. This is technically possible, since the calculation of SV is simple algebra - SV = BCWP = BCWS. It's just simple math.
I struggled for awhile to understand how this concept got confused. That is if SV=0 (you've earned all the value you've planned to earn) AND you're late. What concept was missing, from the persons claiming this was a serious flaw in Earned Value.
What's missing is best explained in a Douglas Adams quote (remember him from Hitch Hikers Guide to the Galaxy)
I love deadlines. I like the whooshing sound they make as they fly by.
So let's try and see where the problem starts. Here's a short explanation.
View more presentations from Glen Alleman.
Now when you hear that "Earned Value has a serious problem, because you can be late and still have SV=0, you'll know what the problem is...
That person was not paying attention when the deadline (the planned finish date) went whooshing by them.
