Designers are comparing concepts or doing "trade-offs" of alternative component designs throughout the design process. They weigh the various ideas against the design criteria and see which one(s) come out best. Much of the time the designer does this in his or her head. However it is often helpful, especially when working with a group or a complex problem, to write down the pros and cons of each idea.

Some examples of pros and cons for a particular transmission design (a gear drive in this case) are:
Pros Cons
  • Reliable
  • High efficiency
  • Won't slip
  • Harder to build and align properly
  • Harder to find meshing gears
  • Harder to modify ratio

In addition to presenting all relevant information in a single place, the record of ideas also allows the designer to go back later and choose another design if the first one selected does not work out.

Once designs of individual components have been evaluated and one or two leaders identified, students can begin to integrate then into a complete car design. The design for the complete car will be a combination of the students' most workable components. The deciding factor in the choice between two or more workable options for a particular component may be its compatibility with the rest of the car's design. If concepts generated thus far are not sufficient, it may be necessary to refer to brainstorming notes and/or generating more ideas.