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Evaluate Alternatives Evaluate Alternatives
OverviewOverview
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 StrategyThe Process of Selecting a Strategy
We now have developed alternatives, we must
Select the best Discard the inappropriate Sustain other potential alternatives Provide decision makers with guidance in their
selection
Always consider our planning opportunities, objectives, and constraints.
Conflict Between Roles of Analyst and Decision Maker
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
Analystexplorationvariationsensitivity
trade studies
Decision Makerpolitical realities
acceptabilitychanges in public perception
legislation
Words of WisdomWords of Wisdom
Although we identified alternatives we still need a top-down approach in the selection process,
Screening Selection Analysis
With increasing attention to: Completeness Effectiveness Acceptability Efficiency
Overview of the Selection ProcessOverview 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 StudiesTrade Studies
Within the aerospace industry, this analytical process is termed “trade studies”
Derived from trade-off analysis
Parametrically explore response of system to changes in input or transformations
Develop surface response curves
Emphasis on life cycle
Functions, Requirements, Architecture and Testing
Functions, Requirements, Architecture and Testing
Problems became more complex and... Engineering specialization led to difficulties Need for common information and database No individual could track entire process Coordination and system management became
essential
Systems Engineering emerged and...
Functions, Requirements, Architecture and Testing (FRAT)
FRATFRAT
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
ComparisonsComparisons
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
Define functional relationships between sub-problems
Identify life cycle costs
Multi-Objective Programming (MOP) and Planning
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
Decision Making Context
Single Decision Makeror Decision Group
Multi-Objective Solution Methods
Bottom-UpInformation Flow
Generating Techniques
Top-DownInformation Flow
Techniques thatIncorporate Preferences
Conflict Resolution
Multiple DecisionMaker Methods
Classifications of MOP ApproachesClassifications of MOP Approaches
MOP FormulationMOP 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 InferiorityNon 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.”
MaximizePower
Environmental Quality
Correspondence exists between feasible region in decision space and the feasible region in objective space.
Size of InstalledTurbine
Minimum Instream Fish Flow, in 1000 cfs1 2 3 4 5 6
5
10
15
20
25
30
5 10 15 20 25 30 35
Power Production
Environmental Quality
Classifications of MOP ApproachesClassifications of MOP Approaches
Decision Making Context
Single Decision Makeror Decision Group
Multi-Objective Solution Methods
Bottom-UpInformation Flow
Generating Techniques
Top-DownInformation Flow
Techniques thatIncorporate Preferences
Conflict Resolution
Multiple DecisionMaker Methods
Generating TechniquesGenerating 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 TechniquesPreference 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 MethodAnalytical Hierarchy Method
Method widely introduced by Thomas L. Saaty
Requires hierarchical organization of problem
Performed by comparing activities at different levels
Uses pair-wise comparisons
An Example:An Example:
Purchase a Car
Cost Comfort Reliability Power
Rabbit Subaru Wagon Jaguar
The ScaleThe Scale
With respect to Cost, compare alternatives Rabbit and Subaru
Score Meaning1/9 A is absolutely less important than B
1/7 A is demonstrably or very strongly less important than B
1/5 A is less important than B
1/3 A is weakly less important than B
1 A and B are equally important
3 A is weakly more important than B
5 A is more important than B
7 A is demonstrably or very strongly more important than
9 A is absolutely more important than B
The Process of AHPThe Process of AHP
Pair-wise comparison matrices are generated at each level
The eigen value is taken of each matrix for a final ranking of alternatives at each level
Measures of consistency are generated
Reaching ConsensusReaching Consensus
Bring scoping and evaluation process to closure Select a strategy Implement a plan
What is required to accomplish these goals? Plans must be perceived as fair, feasible, and
implementable Consensus is a key element in these outcomes
Different Paths to Agreement (Lamb 1990)Different Paths to Agreement (Lamb 1990)
Competitive - “a hard competitive strategy characterized by martial tactics & grudging reluctance to compromise”
Cooperative - a “cooperative strategy of give and take, aimed at learning the weakness of the other side”
Integrative - “a principled negotiation
Creating Consensus RequiresCreating Consensus Requires
Communication
Cooperation
Compromise
Incentive
The DPS Planning Process builds consensus throughout plan development
Plan Development & Consensus Building: A Common Path
Plan Development & Consensus Building: A Common Path
Consensus Building Process Planning Process Pre-Negotiation Phase
• Getting started • Assemble a team
• Representation • Identify problems and
• Drafting protocols establish planning
& setting the agenda objectives
• Joint fact-finding • Define the status quo
Consensus Building Process Planning Process Negotiation Phase
• Inventing options for • Formulate alternatives
mutual gain • Evaluate alternatives and
• Packaging agreements select strategy
• Producing a written
agreement
• Binding the parties to
their agreements
• Ratification
Plan Development & Consensus Building: A Common Path
Plan Development & Consensus Building: A Common Path
Plan Development & Consensus Building: A Common Path
Plan Development & Consensus Building: A Common Path
Consensus Building Process Planning Process Implementation orPost-Negotiation Phase
• Linking informal • Implement plan
agreements to formal • Maintain & exercise plan
decision making
• Monitoring
• Creating a context
for renegotiations
Tips From The Experts... Getting to Yes (Fisher & Ury 1991)
Tips From The Experts... Getting to Yes (Fisher & Ury 1991)
Separate the people from the problem
Focus on interests not positions
Invent options for mutual gain
Insist on using objective criteria
Tips From The Experts... Moving Towards Closure (Cormick 1987)
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
Tips From The Experts... Obstacles to Consensus
Perceptions of inequity
Unmet interests
Fear of losing face
Impending deadlines
Tips From The Experts... Getting Past No (Ury & Fisher)
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 ConsensusWhen There Is Not Consensus
Conclude the discussions
Identify areas where participants “agreed to disagree”
Emphasize what was achieved
A Final Step to Plan SelectionA Final Step to Plan Selection
Produce a written agreement to
Ensure that the parties have heard and understood each other
Provide something concrete for representatives to take back to their members for review and ratification
The “Single Text” ProcedureThe “Single Text” Procedure
A draft is created by an individual or working group
Participants review and modify the document until closure is reached
The text is viewed as a working draft throughout this process
Participants are asked to improve rather than criticize
SummarySummary
Numerous techniques exist for alternative evaluation
Multiobjective programming offers range of approaches
AHP provides techniques to incorporate subjective information
Consensus building is essential step in alternative selection
ExerciseExercise