Scrum: A Value-Driven Approach
Scrum: a value-driven approach
The belief is, that a value-driven approach like Scrum, which dispenses with a "complete plan" up-front, sacrifices the predictability of a plan-driven approach. This belief would have merit if there were any evidence that software and other complex creative development projects were predictable even in principle. The history of software development suggests strongly that they are not. The work of software guru Steve McConnell (building on the work of Barry Boehm) suggests that project estimates at the beginning are wildly speculative (wrong by a factor of four).
Based on Barry Boehm's well-known Cone of Uncertainty, which is predicated on a single-pass, phased development model (aka "the waterfall" approach), we can see that we don't have anything like predictability until perhaps halfway through the project timeline. Not only that, but the observed rate of project failure in the software industry (according to recent reports) tells us that only 32 percent of software projects are successful. This implies that achieving predictability and control using a plan-driven approach is the real myth.
In addition, Scrum provides its own set of metrics (based on empirical observation of sprint results) that absolutely allow strategic planners to monitor project health and progress as well as, or better than, traditional methods. So, then, it's clear that the bar is pretty low for increasing project performance. The truth of the matter is that Scrum will not greatly improve the initial predictability of our projects but it certainly can't do worse.
That said, with Scrum's emphasis on delivering the highest value features first, eliminating features that contribute negligibly to ROI and continually evaluating what's most important, Scrum will deliver the best product we possibly can-with the time, money and people we have. In addition, Scrum doesn't make us wait until halfway into a project to tell us if we're in hot water or not.