Why software estimates change and inflate
As a software developer (Architect?) I find myself in a constant battle with clients and project managers about changing estimates and their inaccuracy. I've lost count the number number of times I've given an estimate and then had to revise it to the dismay of folks who assumed seemingly subtle changes would move the estimate down or allow it to remain the same, only to see it creep up. There are a number of variables that increase the estimation risk and I'll briefly touch on the major factors. Major factors are: Changing requirements/assumptions - a fundamental truth is that any change incurs overhead. The act of changing the design to remove a requirement is is work too...remember, even simplifying the design is work. Removing a requirement mandates revalidating a design against (even if they're simplified) the new requirements. Changing the team structure - an experienced dev is much more effective than a newbie. Moreover a person well versed in a parti...