1. Welcome W 6.1 Introduction to Engineering Design II (IE 202)
Chapter 3: Measuring Things 1 1

2. Today’s Learning Outcomes
By the completion of today's meeting, students should be able to:
Be able to rank the client’s objectives.
Establish assessment scales for measuring success in achieving objectives. 2 2

3. Preview What have we covered so far? Overall Design Process
Project Management
Problem Definition (Identifying Client’s Objectives) 3 3

4. 1st Task in the Design Process4 4

5. What’s Next? Having defined the client’s objectives
How do we know it had been achieved? Measurement scales
Are there any priorities among them? Setting weights 5 5

6. Measurement Basics Defined reference (e.g. zero)
Units (e.g. oC, m, kg, sec.)
These enable strong measurement. 6 6

7. Design scales are usually Subjective.
Nominal scales; for differentiation
Partially ordered scales; father & son
Ordinal scales; 1st, 2nd, 3rd, …
Ratio scales; cm, sec., $, …
Interval scales; oC
Multidimensional scales; km/hr
Design scales are usually Subjective. 7 7

8. Creativity Break
How can cut these cakes into 3
equivalent parts? 8 8

9. Setting Priorities
Are all objectives of the same importance to the client?
Is it an important issue?
The basic measurement scheme:
more/less – better/worse
The Golden Rule:
Don’t mix apples with oranges, compare apples with apples and oranges with ora. 9 9

10. Pairwise Comparison Chart
PCC is a table constructed to evaluate the objectives. It is a simple straightforward rank ordering scale.
Each team member constructs his own table.
The overall weight is found by simple averaging.
Team consensus may be used instead.
Arrow Impossibility
decision theorem by
K. J. Arrow (1972) =>
Noble Prize in eco. 10 10

11. Juice Container for the Kids a sheet of paper and hand
As teams: Is it OK to ignore the one with 0 score? Explain why?
Example Using PCC
Juice Container for the Kids
Write your answers in
a sheet of paper and hand
it to your instructor.
As teams: What is the criterion, the row cell or the column cell? Explain why. 11 11

12. Note: PCC is not Weighted ranking
PCC Aggregate Ordering
What if we have a team of designers?
Suppose this is the result of 12 votes:
 A > B > C  B > C > A
A > C > B  C > B > A
What is the result of the vote? C > B > A
Note: PCC is not Weighted ranking 12 12

13. Metrics How can one measure achievements?
What if your doctor said
Your eye pressure is 15?!
What should you answer?
What is the ideal?
Metrics
How can one measure achievements?
Metric: actually measure the objective.
Appropriate units & Correct scale, e.g.
Ladder weight: cm kg Tons mg SR sec. ?
Next, assign points, e.g. 50 – 200 km/hr
0 point: 50 km/hr, 100 points: 200 km/hr
Cellphone Durability: drop tests of 1-3 m 
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14. Measurement Plan There must be a measurement plan:
Direct/calculated measurement
Estimated measurement
Consumer surveys
But, may not be available until …
Popular scales: high/medium/low or
str.agree/agree/notdec/disagree/str.disagr
Do you know of
a similar system?
Your grades!
Likert Scale
1, 2, 3, 4 & 5
German VDI 2225
0, 1, 2, 3 & 4
Use-Value Analysis
0: absolutely useless
10: ideal, How many? 14 14

15. Remarks on Metric Assess.
All assessment has to be done consistently on the same scale.
A metric should be repeatable
Outcomes should be expressed in understandable units of measure.
The results should lead all parties involved in the design process to the same conclusion. 15 15