In the concurrent engineering methodology all task will be as much as possible processed in parallelization.
In the traditional sequential design flow, or "Waterfall Model” tasks wil be processed in a linear fashion. Starting with requirements and sequentially moving forward to design and implementation, until there is a finished product. In this design system, a design team would not quickly look backward or forward to anticipate on problems. In the case that something does go wrong, the design usually must be scrapped or heavily altered. This will take time, cost and frustration.