Week 10- Decision analysis Flashcards
When to do decision analysis
- Uncertainty in decision criteria
- multi-objectives
- multi-criteria
Multi-Criteria Analysis approach
- objective
- alternative states
- Select criteria (e.g exclude development within 25m of stream)
- Standardise criteria
- weights
- combine scores
- Ranking alternatives
- Sensitivity anal
what to do when both Multi-objectives and multi-criteria
-prioritise objectives
constraints
-areas that cannot be allocated to a particular land use
Criteria Standardisation Functions
Calculated with map algebra:
- directionality (closer to road is better)
- shape (suitibility score is uniform –>assumption of linearity)
- thresholds (>20km score is 0 (least suitable))
Methods for obtaining weights from stakeholders and calculating
- voting/rating method
- Ranking methods: weight calculated based on rank position.
Decision rules (combining weights and criteria scores)
- additive weighted combination
- Geometrical weighted combination
- ideal point method
additive weighted combination rule
- individual criteria compensate for others
- summation
Geometrical weighted combination ruel
- individual criteria limit influence of others
- weighted multiplication
Ideal point method rule
-closeness to an ideal (distance to best score and distance from worst)
Multi-objective decision conflict
-conflict objectives where both objective want the same area (i.e development vs conservation)
Sensitivity analysis
How strongly results hold given methodology.
- do small changes in parameters of criteria functions and weights produce big changes in result
- Ideal: less sensitive
What would prompt a sensitivity analysis?
uncertainty about which criteria is most important
