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82 A Guidebook for the Evaluation of Project Delivery Methods
To achieve the weighted ranking, owners should do the following:
· Rank the selection factors in order from highest to lowest with regard to their influence on
project success.
· Include a minimum of four and a maximum of seven factors.
Remove factors not ranked in the top seven.
· Using 100 total points, weight the factors according to their influence on project success.
Avoid equal weighting of factors.
Remove any factors with a value of less than 5 of the 100 points and redistribute points.
These three steps describe a simple method for achieving a weighted ranking of the selection
factors. Decision sciences provide more precise methods for achieving weighted rankings and
developing a consensus. Appendix F (available on the TRB website at http://trb.org/news/
blurb_detail.asp?id=10054) provides descriptions of the following methods to achieve more
precise weighted rankings:
· The Delphi Method,
· Rank Order Centroid,
· The Ratio Method, and
· Pairwise Comparison.
The result of Step 2 will be a weighted ranking of up to seven selection factors. The weightings
should total 100 points. Equal factor weightings are not recommended because distinguishing
the importance between factors (goals and pertinent issues) is necessary for the decision process.
Additionally, no single factor should have a point value of less than five because a point value
that low will not influence the final decision and may in fact make the selection more difficult.
Steps 3, 4, and 5 involve combining the weighted ranking of the selection factors with a scoring
of the project delivery methods to arrive at the selection of the most appropriate delivery method.
Delivery Selection for the Example Project--Step 2. Table 5.1 shows how weighted ranking
worked in the example project. In Table 5.1, selection factors for the example project have been
weighted to reflect their influence on the success of the example project's delivery. These weight-
ings are project dependent and should be agreed upon by key owner team members.
Step 3. Score Project Delivery Methods
The third step involves a scoring of the alternative delivery methods from the Tier 1 analysis.
Each of these delivery methods will have a bearing or influence on the selection factors, which
stem from the project goals and pertinent issues. The key decision makers must translate this
influence into a score to arrive at a decision. To achieve the total scores for each delivery method,
owners do the following:
Table 5.1. Weighted ranking of selection factors for the
example project.
Weight Selection Factor
50 Project complete by November 1, 20XX.
25 Cost not to exceed $1.5 billion.
15 Environment enhanced through less traffic congestion and pollution.
10 Staffing requirements minimized during design and construction.
100 Total
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Tier 2--Weighted-Matrix Delivery Decision Approach 83
· Using the scale given in Table 5.2, assign a score to each delivery method that represents its
influence or bearing on each selection factor. Score all delivery methods for each factor before
moving to the next factor.
· Repeat the previous step for each selection factor.
· When all of the delivery methods have been scored, multiply each delivery method's factor
weight by its score to achieve a weighted score for each delivery method.
· Sum all of the weighted scores to arrive at a total score for each delivery method.
Table 5.2 provides a scale for scoring each delivery method's bearing on each selection factor.
The scores range from 1 to 10 so that when they are multiplied by the factor weight, the total score
will range from 0 to 1,000. The scores are subjective, so a detailed definition for each numerical
score is provided adjacent to the score in Table 5.2. When scoring the delivery methods, owners
should discuss the advantages and disadvantages of each delivery method (see Chapter 3 and
Step 4 of Tier 1). The alignment of these advantages and disadvantages with the selection factors
forms the basis for the scoring. In assigning the scores, the owner should work in a team to come
to a decision by consensus. The reasons for each individual score should also be carefully doc-
umented. Consideration should also be given to the relative scores for each delivery method
to ensure consistency.
Like the development of factor weights, scoring project delivery methods can be done most
simply through a group discussion among key decision makers from the owner's team. If a
more precise scoring is desired, one of the decision techniques described in Appendix F can
be used.
Table 5.3 provides a weighted decision matrix template. The matrix can contain up to four
delivery methods, depending upon the results of Tier 1. The matrix can also contain up to seven
selection factors for each project. The result of Step 3 will be a scored ranking of the delivery
methods in question. The delivery method with the highest total score will be the most appro-
priate method for the given project.
The next steps involve documenting the individual scores, making a decision, and creating a
Project Delivery Selection Report.
Delivery Selection for the Example Project--Step 3. Table 5.4 shows how an owner might
score the project delivery methods for the example project. Note that only the CMR and DB
project delivery methods made it through the Tier 1 filter for further consideration in Tier 2.
Also note that the scores are project dependent and will certainly change from project to project.
Table 5.2. Project delivery scoring scale (adapted from Saaty 1990).
Score Definition
10 The evidence that the delivery method positively aligns with the project objective or
issue is of the highest possible order of affirmation.
8 The delivery method strongly aligns with the objective or issue and is demonstrated
in practice. There is a slight risk that the objective or issue may not be beneficial.
6 Experience and judgment point to the delivery method strongly aligning with the
objective or issue. There is a mild risk that the objective may not be beneficial.
4 Experience and judgment point slightly to the delivery method aligning with the
objective or issue. There is a strong risk that the objective will be negatively
affected.
2 There is little benefit to applying the delivery method for this goal or objective.
There is a strong likelihood that the object will not be achieved.
9,7,5,3,1 Intermediate values between two adjacent judgments.
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84 A Guidebook for the Evaluation of Project Delivery Methods
Table 5.3. Weighted-matrix template.
Project Delivery Method
DBB CMR DB DBOM
Selection Factor Weighted Weighted Weighted Weighted
Score Score Score Score
Factor Weight Score Score Score Score
Factor 1
(e.g., Project
Goals)
Factor 2
(e.g., Agency
experience)
Factor 3
(e.g., Market
issues)
Factors 4 to 7
...
Total Score
Explanations of the scores for the project delivery methods for the example project are the fol-
lowing:
· Project completion factor. The project completion factor relates to a project goal. In this case,
the project has a fixed end date of November 1, 20XX. The owner believes that CMR delivery
can achieve the completion date. The owner also believes that CMR will require the use of
multiple bid packages to achieve the schedule, which adds a risk for meeting the schedule date,
so CMR = 6 (in this case). DB delivery provides for a single entity to coordinate design and
construction. DB also allows for an owner to specify a fixed end date in the procurement doc-
uments and the contract. According to what has been demonstrated in practice, the owner is
confident that the end date can be achieved through a DB delivery, so DB = 8 (in this case).
· Cost containment factor. The cost containment factor relates to a project goal. The project
has a maximum budget of $1.5 billion. Practice has shown that with DB a fixed price can be
set early in the project development process. It has also been demonstrated that DB provides
the lowest average cost growth of the two methods in question, so DB = 8 (in this case). CMR
also provides the ability to meet a fixed price, but the owner is not as confident with the expe-
rience using a GMP contract structure. The owner also feels that there is more risk with CMR
of not achieving the schedule than with DB, so CMR = 6 (in this case).
Table 5.4. Weighted matrix for example project.
Project Delivery Method
CMR DB
Factor Weighted Weighted
Selection Factors Score Score
Weight Score Score
Project complete by November 1, 20XX 50 6 300 8 400
Cost not to exceed $1.5 billion 25 6 150 8 200
Environment enhanced through less
15 10 150 6 90
traffic congestion and pollution
Staffing requirements minimized during
10 8 80 6 60
design and construction
Total Score 100 680 750
