68 Engineering Fundamentals
problem because of the different constraints
and criteria for each design.
• Economic feasibility. Is it cost effective?
• Ease of production. Can the product be
produced effectively?
• Appearance. Does the product look good?
• Maintenance. Is the product easy to
maintain?
• Marketability. Is the product marketable?
• Convenience. Is the solution convenient for
the user?
• Greenness. Does the product have a
negative impact on the environment?
• Multiple uses. Does the product solve
multiple problems?
The sample matrix shown in Figure 4-16
could be used by an engineer to determine the
best way to move people from home to work
to improve rush hour road congestion. As you
can see, you give points (positive, negative, or
neutral) for each idea under each category. You
then total the points in the fi nal column.
Engineers also consider the criteria and
constraints of the initial problem when analyz-
ing the trade-off matrix. As previously discussed,
a constraint is a specifi c condition that limits the
engineering design solution. A criteria is a rule or
principle that is used as a basis of an engineering
design problem. The constraints and criteria drive
the engineering design process and are revisited
when analyzing the trade-offs to make sure specifi c
design components do not ignore the specifi c
constraints and criteria required for the design.
Selecting the Best
Approach
Once the engineers have gathered all of the
necessary information from their research, it is
time to analyze the data to make the fi nal selec-
tion. Sometimes engineers have one solution that is
clearly better than the other designs, but this is not
always the case. It is important for engineers to rely
on members of their design team and to effectively
communicate their design to those interested in the
engineering process. Those interested in the design
may be project managers, customers, consumers,
engineers, and many other potential stakeholders.
Analyze Data
Depending on the specifi c type of problem the
engineers are solving, there may be many differ-
ent people involved in the data analysis process.
Members of large engineering design teams may
need to present their ideas to others on their team,
along with presentations from the other teammates,
Figure 4-17. In other cases, the engineer may be a
team of one person that needs to present the idea
to their customer or the product manufacturer. In
either case, documentation of the initial designs is
critical to communicating the research fi ndings.
Goodheart-Willcox Publisher
Sample Trade-Off Matrix
Solution Train Monorail Bus Commuter cars
Appearance 0 +1 0 +1
Manufacturability
+1 0 +2 +2
Feasibility
+1 0 +1 –1
Low maintenance 0 +1 –1 –1
Marketability +1 +1 0 +1
Environmentally Friendly +1 +2 0 –1
Total
4 5 2 1
Figure 4-16. 
This sample matrix shows how engineers compare different potential solutions.