Complicating this is the disruption that results from the iterations that are inherent to product development. Consider the challenge of designing for complex products like jet aircraft. Teams of engineers that are organized according to their many specialized functions must design thousands of individual parts, optimizing the system as a whole while making trade-offs between a wide range of disparate performance considerations—like balancing requirements for airframe strength with the need to hold down structural weight. Further, they must consider production issues, reliability, and a host of other competing needs while working to minimize production costs.