Looser Approaches to Predictability

The discussion so far has been based on a pure predictability approach. At some point in the project, the organization wants to be able to predict the exact combination of cost, schedule, and functionality that will ultimately be delivered—without changing any of them very much. The need for this level of predictability is common in some industries and comes up only occasionally in others.

The more common need I see is for a looser level of predictability that allows for ongoing management control of cost, schedule, functionality, or all three. As I’ve written previously, many times the role of estimation is not to make a pin-point prediction but to gain a general sense of whether this general type of work can be completed in that general time frame (McConnell, 2000). This is not really “prediction,” because the entity you’re predicting keeps changing. It’s really a combination of prediction and control. Regardless of how it’s characterized, it can ...