Paragraph 2.3: Weighted Objectives of the Delft Design Guide, for Industrial Design, TU Delft (http://ocw.tudelft.nl)
1.
Keywords
Concept selection
Weighted Objectives Method
Ranking
What Is the Weighted Objectives The Weighted Objectives Method involves assigning
Method? weights to the different criteria. This allows the
weight concept 1 concept 2 concept 3
The Weighted Objectives Method (see figure 2.62) is decision-maker to take into account the difference in
controllable on
2 5 2 2 an evaluation method for comparing design concepts importance between criteria.
velocity and direction
based on an overall value per design concept. The
safe 3 6 3 3
biggest disadvantage of using the Datum Method When Can You Use the Weighted
gain enough speed 4 3 4 4
or the Harris Profile is that the scores per criterion Objectives Method?
basic construction
1 7 5 1 cannot be aggregated into an overall score of the The Weighted Objectives Method is best used when
simple
design alternative. This makes a direct comparison a decision has to be made between a select number
well accesible parts 2 8 5 2
of the design alternatives difficult. The Weighted of design alternatives, design concepts or principal
distinct 4 4 7 4
Objectives Method does exactly this: it allows the solutions. Usually, the Weighted Objectives Method is
stable 3 3 8 3
scores of all criteria to be summed up into an overall used when evaluating design concepts, and to make
compact 1 6 3 1
value per design alternative. a decision as to which design concept should be
springs 1 8 2 1
The Weighted Objective Method assigns scores to developed into a detailed design.
price 3 7 5 3
the degree to which a design alternative satisfies
total score 125 130 89
a criterion. However, the criteria that are used to
evaluate the design alternatives might differ in their
fig. 2.62 Example of Weighted Objectives Mehtod importance. For example, the ‘cost price’ can be of
(from student report) less importance than ’appealing aesthetics’.
How to
Weighted 1
concept concept 19
2 2
Objectives criteria criteria
5 criteria 10
Method 3 criteria 7
limited number select criteria assign weights make matrix attribute values for each calculate score.
of concepts for selection to criteria (1-5) concept how it meets a concept with highest
criteria with a score 1-10 score is preferred
Delft Design Guide | Part 2 | Decision and Selection | Weighted Objectives Method – 2.3
2.
Delft Design Guide | Part 2 | Decision and Selection | Weighted Objectives Method – 2.3
How to Use the Weighted Objectives 5 Attribute values to how each concept meets a
Method? criterion. Rank the scores of the concepts from
Starting Point 1 to 10.
A limited number of concepts. 6 Calculate the overall score of each concept by
summing up the scores on each criterion (make sure
Expected Outcome you take into account the weight factor).
A chosen concept. 7 The concept with the highest score is the preferred
concept.
Possible Procedure
1 Select the criteria according to which the selection Tips and Concerns
will be made. These criteria should be derived from • This method should be carried out intelligibly, while
the programme of requirements (note that probably discussing and reviewing both the weights assigned
not all requirements are applicable at this stage of the to the criteria and the scores of the concepts
design process). according to all the criteria.
2 Choose 3 to 5 concepts for selection.
3 Assign weights to the criteria. The criteria should be References and Further Reading
appointed weights according to their importance for Roozenburg, N.F.M. and Eekels, J. (1995) Product Design:
the evaluation. To determine the weight factor of Fundamentals and Methods, Utrecht: Lemma.
the criteria it is recommended that you compare the
Roozenburg, N. and Eekels, J. (1998, 2nd ed.) Product
criteria in pairs to attribute a weight factor. Rank each
Ontwerpen: Structuur en Methoden, Utrecht: Lemma.
of the weights on a scale from 1 to 5 (you can also
decide on a total sum of the weights of the criteria,
for example 100). Make sure you discuss the trade-
offs between the criteria. Trade-offs will have to be
made when weights are assigned to the individual
criteria (when you are determining which of the
weights are more important).
4 Construct a matrix, with the criteria in rows, and the
concepts in columns.
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