Right. So you don't do that. No development process ever has provided bulletproof predictability. Your job as a project manager is not to provide bullet-proof predictions; it's to manage risk, and expectations, and make sure that development work is correctly prioritized. And of course to keep your development team protected from external insanity, because happy, stress free development teams are productive development teams. (But that's a separate issue).
Here's the feature list; here is where on the list we'll definitely get to, here's where on the list we definitely won't get to, and everything else is some shade of inbetween. Now, would you like to adjust the priorities of any of those features, or would you like to change the deadline?
Here's the feature list; here is where on the list we'll definitely get to, here's where on the list we definitely won't get to, and everything else is some shade of inbetween. Now, would you like to adjust the priorities of any of those features, or would you like to change the deadline?