SPE Strategies and Scenarios
In SPE, a strategy is not only a label. It is a set of scenarios that change Driver states and allow the model to evaluate outcome distributions.
Strategy
A Strategy is a named decision alternative or family of alternatives. It should have a definition that explains the action being considered and the decision frame.
Scenario
A Scenario belongs to a strategy. In the current Workbench, a scenario assigns direct impacts to Driver variables using the five-state scale:
- NN: very negative direct impact
- N: negative direct impact
- O: neutral or no direct impact
- P: positive direct impact
- PP: very positive direct impact
The scenario is calculated by applying those Driver impacts, running the model through the cross-impact structure, and summarizing the resulting Outcomes.
Manual and combinatorial scenarios
Manual scenarios are entered directly by the user. Combinatorial strategies use options and alternatives to generate multiple scenarios from combinations.
Use manual scenarios when you already know the alternatives to compare. Use combinatorial scenarios when a strategy has several design dimensions and you want Albarena to generate the scenario list.
Comparison first
Avoid presenting only one absolute prediction. A more useful SPE story is:
- Scenario 1 improves Outcome A compared with Scenario 2.
- Scenario 1 increases risk in Outcome B compared with Scenario 2.
- Scenario 2 is less attractive on expected value but more robust under unfavorable context.
- The difference between scenarios is larger than the uncertainty range the team cares about.
Future combined-scenario evaluation
PLACEHOLDER: Albarena will incorporate combined scenario evaluation. The planned capability is to combine one scenario from Strategy A with one scenario from Strategy B and calculate their simultaneous impact. This may produce a different result than evaluating Scenario 1 of Strategy A and Scenario 1 of Strategy B separately, because the impacts occur at the same time.