Business underperformance in the upstream oil and gas industry, and the failure of many decisions to return expected results, has led to a growing interest over the past few years in understanding the impacts of decision-making tools and processes and their relationship to decision outcomes. A primary observation is that different decision types require different decision-making approaches to achieve optimal outcomes. Optimal decision making relies on understanding the types of decisions being made and tailoring the type of decision with the appropriate tools and processes. Yet the industry lacks both a definition of decision types and any guidelines as to what tools and processes should be used for what decisions types. We argue that maxim...