The challenge in this phase is determining when you have collected adequate information to lead to a viable and economical solution. System specification System specifications are measurable characteristics that describe the behavior of a system or action that solves the problem identified in the above engineering phase. Specifications constrain the solution to having a finite set of characteristics. Some of these characteristics have ranges of acceptable operation while others have exact attributes. Specifications are the targets that the solution must shoot for.
Specifications have a secondary function of validation.
During subsequent design activities, the proposed solution must be tested for compliance to the specifications. If the problem definition phase was correctly completed and the proper specifications generated, the problem will be solved if and only if the solution system meets all the specifications. All other problems require a methodical search for possible solutions. At this point in the design phase, gather as many possible solutions as can be found. There will probably be many good potential solutions but few, if any, that exactly meet the requirements.