Structured Analysis

Analyses can be performed using the Patchworks interface as outlined in Controlling Patchworks. Targets are adjusted in the target charts, and activated or de-activated at the Targets panel. Even treatments can be manually added or deleted. This "Ad Hoc" method has certain disadvantages though. It is sometimes hard to remember the rationale for the changes you have made and the documentation of those changes is not automatic. You can quickly become muddled! In order to analyze and compare the impact of changing objectives and constraints of selected indicators, a protocol for doing sensitivity analysis is strongly advised. A methodical exploration of issues would include the following steps:

  1. Plan

    • What issues/factors are you considering?

    • What indicators do you need to develop for these factors?

    • How will you model volume, costs, or habitat?

    • What would you like to compare?

    • What management strategies and policies should be tested?

  2. Analyze

    • Code model controls into small reusable components.

    • Build a library of model components.

    • Combine components into distinct scenarios.

    • Run scenarios using batch scripts (see Automating Patchworks for more information and examples).

  3. Reflect

    • Organize your scenario output in such a way that it is easy to compare and contrast indicators.

    • Use comparison reports, posters, animations and web site tools.

    • Present results to external reviewers.

    • Objectively consider weaknesses of the model.

    • Search for anomalies and inconsistencies.

  4. Repeat

    • Continue running scenarios until you are satisfied with the results.

Scenario modeling allows the user to define a detailed and specific set of objectives that can be evaluated against a number of constraints. Then these can be adjusted and compared against previous combinations of objectives and constraints.