8. The Right Decision
Design decisions should be
based on analysis and
logic, not personal opinion.
A decision matrix is a
design tool that may be
used multiple times
throughout a design
process.
Editor's Notes
A decision matrix is used to compare design solutions against one another using specific criteria. Design problem constraints are identified by the customer in the workplace. For classroom purposes, the student teams will be provided the constraints and will be required to develop a decision matrix.
A decision matrix is a design tool that may be used multiple times throughout a design process.
Identify criteria such as cost, reusability, geometry, connections, cleanliness, resilience, and testability.
Other types of criteria are function, product life span, development time, size, material costs, development costs, manufacturing costs, company standards, manufacturing capabilities, and safety. This is a sample list only; it is not all inclusive for criteria.
A grading scale must be developed to assign values for each criteria category.
Here are a few grading scale examples that can be used to evaluate the design ideas. Keep in mind that teams can also create their own and submit the scale for approval.
The items listed at the top of the matrix are the constraints for the design problem. These constraints are typically identified by the client; however, for this example they were self-generated.
The items listed on the left side of the matrix are the brainstorming solutions for the design problem. These are generated by student teams.
The Reusable and Self-Adhering columns are examples of constraints that utilize the Question Scale (bottom right).
All other constraints utilize the Rank Scale (bottom left) to identify the best solution to the design problem.
The column on the right side of the matrix is the Total of the rankings for all constraints per proposed design solution. The solution with the highest total is considered the best solution to the design problem. Design decisions should be based on analysis and logic, not personal opinion. For this example, the interlocking centimeter cubes are the best solution to the design problem.
