Progressive Refinement

With sequential product development all requirements must be at the same level of detail at the same time. In particular, the approved requirements document must specify each and every requirement so that the teams doing the design, build, and test work can understand how to conform to the specifications. There are no details left to be added.

Forcing all requirements to the same level of detail at the same time has many disadvantages:

• We must predict all of these details early during product development when we have the least knowledge that we’ll ever have.

• We treat all requirements the same regardless of their priority, forcing us to dedicate valuable resources today to create details for requirements that we may never build.