Transcript Evaluate Alternatives - University of Washington

Evaluate Alternatives
Overview
In this section we will discuss the selection
among alternatives

The roles of analysts and decision makers

Trade-studies

Functions, requirements, and architecture

Multi-objective decision making

Reaching consensus
The Process of Selecting a Strategy
We now have developed alternatives, we must

Select the best

Discard the inappropriate
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Sustain other potential alternatives
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Provide decision makers with guidance in their
selection
Always consider our planning
opportunities, objectives,
and constraints.
Conflict Between Roles of
Analyst and Decision Maker

A skilled analyst incorporates preferences into
an analysis

A skilled decision maker recognizes that factors
outside of the analysis may also be important
Analyst
Decision Maker
exploration
variation
sensitivity
trade studies
political realities
acceptability
changes in public perception
legislation
Words of Wisdom
Although we identified alternatives we still need a
top-down approach in the selection process,

Screening

Selection
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Analysis
With increasing attention to:

Completeness
Effectiveness

Acceptability
Efficiency
Overview of the Selection Process
Compare alternatives
 Analytical
 Subjective
Rank alternatives
Seek consensus
Modify alternatives to address concerns
Adopt an alternative
In all phases of this process, both quantitative
and subjective information must be included.
Trade Studies
Within the aerospace industry, this analytical
process is termed “trade studies”

Derived from trade-off analysis
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Parametrically explore response of system to
changes in input or transformations
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Develop surface response curves
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Emphasis on life cycle
Functions, Requirements,
Architecture and Testing
Problems became more complex and...
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Engineering specialization led to difficulties
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Need for common information and database
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No individual could track entire process
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Coordination and system management became
essential
Systems Engineering emerged and...
Functions, Requirements, Architecture and
Testing (FRAT)
FRAT
1. Define the system boundaries, inputs and
outputs
2. Define what the system must do (Functions)
3. Define how well these functions must be
performed (Requirements)
4. Identify and evaluate multiple alternatives
5. Define the best answers (Architecture)
6. Perform tests to ensure system performance
Comparisons
There is a clear relationship between water
resources planning and FRAT methodology
Major difference is FRAT’s emphasis on
structured approach

Divide complex problem into sub-problems
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Define functional relationships
between sub-problems

Identify life cycle costs
Multi-Objective Programming
(MOP) and Planning
MOP
 Recognizes that “real world” problems contain
multiple, conflicting objectives
 Maximize system reliability, minimize
environmental impacts, maximize power
production
 Maintains metrics of performance in “appropriate,
natural and descriptive” units - unlike dollars
 Facilitates the generation of objective
function
trade-off curves
Classifications of MOP Approaches
Decision Making Context
Single Decision Maker
or Decision Group
Conflict Resolution
Multi-Objective
Solution Methods
Multiple Decision
Maker Methods
Bottom-Up
Information Flow
Top-Down
Information Flow
Techniques that
Generating Techniques Incorporate Preferences
MOP Formulation
In water resources, most MOP problem
formulations are optimizations:
Max Z(x1,x2.....xn)
such that gi(x1,x2,....xn)<=0
xj>0
Where Z’s are a vector of multiple objectives
and X’s are decision variables
Within water resources literature, most
formulations are linear programs.
Non Inferiority
“A solution to MOP is non-inferior if there exists
no other solution that will yield an improvement
in one objective without causing a degradation in
at least one other objective.”
Maximize
Power
Environmental Quality
Correspondence exists between feasible region in decision
space and the feasible region in objective space.
Size of Installed
Turbine
1
2
3
4
5
6
Minimum Instream Fish Flow, in 1000 cfs
30
25
Power Production 20
15
10
5
5 10 15 20 25 30 35
Environmental Quality
Classifications of MOP Approaches
Decision Making Context
Single Decision Maker
or Decision Group
Conflict Resolution
Multi-Objective
Solution Methods
Multiple Decision
Maker Methods
Bottom-Up
Information Flow
Top-Down
Information Flow
Techniques that
Generating Techniques Incorporate Preferences
Generating Techniques
Develop information about a problem allowing the
range of choice and trade-offs among objectives to
be understood
This is a combination of further analysis and
selection among alternatives
Goal is generation and evaluation of alternatives in
terms of objectives
Goal is not political analysis or prediction
Examples
 Weighting method
 Constraint method
 NISE
Preference Techniques
Require decision makers to articulate their
preferences
Goal is to incorporate the decision maker’s
preference into analytical framework
Once articulated, the preferences help define
non-inferior region
Examples
 Prior assessment of weights
 Goal programming
 Surrogate worth trade-off method
Analytical Hierarchy Method
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Method widely introduced by Thomas L. Saaty
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Requires hierarchical organization of problem
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Performed by comparing activities at different
levels
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Uses pair-wise comparisons
An Example:
Purchase a Car
Cost
Comfort
Reliability
Rabbit
Subaru Wagon
Jaguar
Power
The Scale
With respect to Cost, compare alternatives Rabbit and Subaru
Score
Meaning
1/9
1/7
1/5
1/3
1
3
5
7
9
A is absolutely less important than B
A is demonstrably or very strongly less important than B
A is less important than B
A is weakly less important than B
A and B are equally important
A is weakly more important than B
A is more important than B
A is demonstrably or very strongly more important than
A is absolutely more important than B
The Process of AHP
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Pair-wise comparison matrices are generated
at each level
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The eigen value is taken of each matrix for a
final ranking of alternatives at each level
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Measures of consistency are generated
Reaching Consensus
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Bring scoping and evaluation process to closure
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Select a strategy
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Implement a plan
What is required to accomplish these goals?
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Plans must be perceived as fair, feasible, and
implementable
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Consensus is a key element in these outcomes
Different Paths to Agreement (Lamb 1990)
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Competitive - “a hard competitive strategy
characterized by martial tactics & grudging
reluctance to compromise”
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Cooperative - a “cooperative strategy of give
and take, aimed at learning the weakness of
the other side”
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Integrative - “a principled negotiation
Creating Consensus Requires
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Communication
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Cooperation
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Compromise
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Incentive
The DPS Planning Process builds consensus
throughout plan development
Plan Development & Consensus Building:
A Common Path
Consensus Building Process
 Pre-Negotiation Phase
• Getting started
• Representation
• Drafting protocols
& setting the agenda
• Joint fact-finding
Planning Process
• Assemble a team
• Identify problems and
establish planning
objectives
• Define the status quo
Plan Development & Consensus Building:
A Common Path
Consensus Building Process
 Negotiation Phase
• Inventing options for
mutual gain
• Packaging agreements
• Producing a written
agreement
• Binding the parties to
their agreements
• Ratification
Planning Process
• Formulate alternatives
• Evaluate alternatives and
select strategy
Plan Development & Consensus Building:
A Common Path
Consensus Building Process
 Implementation or
Post-Negotiation Phase
• Linking informal
agreements to formal
decision making
• Monitoring
• Creating a context
for renegotiations
Planning Process
• Implement plan
• Maintain & exercise plan
Tips From The Experts...
Getting to Yes (Fisher & Ury 1991)
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Separate the people from the problem
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Focus on interests not positions
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Invent options for mutual gain
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Insist on using objective criteria
Tips From The Experts...
Moving Towards Closure (Cormick 1987)
1. Start with a range of alternatives
2. Periodically summarize areas of agreement and
disagreement
3. Recognize movement, even wrapped in strange ways
4. Have a strategy when dealing with boulders on the road
5. Build big agreements on small agreements
6. Look for packages
7. Look for mutual benefits - expand the pie
8. Use the deadline
Tips From The Experts...
Obstacles to Consensus
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Perceptions of inequity
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Unmet interests
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Fear of losing face
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Impending deadlines
Tips From The Experts...
Getting Past No (Ury & Fisher)
Step 1. Don’t react, go to the balcony
Step 2. Disarm them, step to their side
Step 3. Change the game - don’t reject...reframe
Step 4. Build a golden bridge
Step 5. Make it hard to say no
When There Is Not Consensus
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Conclude the discussions
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Identify areas where participants “agreed to
disagree”
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Emphasize what was achieved
A Final Step to Plan Selection
Produce a written agreement to

Ensure that the parties have heard and
understood each other
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Provide something concrete for representatives
to take back to their members for review and
ratification
The “Single Text” Procedure
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A draft is created by an individual or working
group
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Participants review and modify the document
until closure is reached
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The text is viewed as a working draft
throughout this process
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Participants are asked to improve rather than
criticize
Summary
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Numerous techniques exist for alternative
evaluation
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Multiobjective programming offers range of
approaches
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AHP provides techniques to incorporate
subjective information
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Consensus building is essential step in
alternative selection
Exercise