Phase 4

Analysis/Judicial Phase: Analysis Evaluation

Weighted Evaluation

Weighted evaluation assures optimum decisions. Good decisions are made by placing the proper

emphasis on all criteria. During evaluation it is important to discuss the following areas:

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Needs versus desires

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Important versus unimportant

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Design trade-offs versus required functions

Procedure

The recommended procedure for weighted evaluation has been broken down into two

processes, the criteria weighting process and the analysis matrix. The criteria weighting

process is designed to isolate criteria and establish their weights or relative importance.

1.

On the criteria scoring matrix all criteria important in the selection of alternatives are

listed. Criteria are compared, one against another, this series of comparisons being the

simplest way to achieve the evaluation.

In comparing two criteria, preference for one over the other is scored according to its

strength. (That is, 4=major preference, 3=above average preference, 2=average preference,

1=slight preference). Criteria evaluated as equal are assigned a value of 1 each. Scores are then

tallied, the raw scores brought to a common base (normally 10 is used for the evaluation), and

the criteria and weights transferred to the analysis matrix.

2.

In the analysis matrix, each alternative is listed and ranked against each criterion. The rank

and weight of each constraint are multiplied and totaled. The alternatives are then scored

for recommended implementation. No alternatives are considered that do not meet

minimum criteria.

For example, if the budget is set, any alternative costing more than the budget is dropped.

The same with safety, environment, and codes; no idea is listed unless it meets basic project/owner

requirements.

This is to avoid letting one discipline dominate. Typically, the safety engineer will insist that the

safer item be selected at any cost. The design architect will insist on his design in all cases. The

maintenance engineer will focus on the lower-cost maintenance impact, regardless of other criteria.

The structural engineer will want the most overdesigned foundation system "to be sure". The

electrical engineer will insist on 100% extra capacity to ensure that adequate capacity will be available

in the building for the next 100 years. The mechanical savings energy will wind up becoming the

objective of the building, rather than "housing people".

3.

Attached as an example, is a weighted evaluation of a car purchase.