• A is a decision strategy in which nothing is done until research resolves all key uncertainties
• B is an iterative and adaptive decision strategy, where action is taken before all key uncertainties are resolved.

According to M. Granger Morgan et al. (2009), and decision strategy B is better than A when there is deep uncertainty over decisions, as is the case with climate change . For decision strategy B, policy is continually reassessed based on the success of previous policies, and allowing for information based on new research. See also economics of global warming .

Summary of diagrams

Decision strategy A:

• starts off with (1) identifying the problem at hand. This flows to:
• (2): do research. This flows to:
• (3): gain a full understanding of all the relevant issues. This feeds back to (2) and to:
• (4): identify policy options. This flows to:
• (5): implement the optimal policy. This flows to:
• (6): solve the problem.

Decision strategy B:

• starts off with (1): identifying a problem. This flows to:
• (2): do research. This flows to:
• (3): learn what you can and what you can't know (at least now). This flows to two tasks: (4) and (5):
• (4): identify adaptive policies and choose one that currently looks best. An adaptive policy can be revised based on new evidence. (4) flows to (6).
• (5): continue research. (5) flows to (7).
• (6): implement policy and observe how it works. This flows to:
• (7): Reassess policy in light of new understanding. This flows to:
• (8): Refine problem identification as needed. This feeds back to (4) and (2).