The Oops Game: How Much Planning Is Enough?

Gregory Howell1 & Min Liu2

1President, Lean Construction Institue, Box 1003, Ketchum, Id 83340. +1-208/726-9989;
2Assistant Professor, Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC 27695-7908. PH (919) 513-7920; E-mail:


The future is unknown and unknowable. In the face of this reality, planning tries to assure an outcome certain. The “Oops Simulation” (Oops) models the dilemma experienced by every planner: “Should I spend more (time, money, resources) to improve my plan or go forward with what I have and more likely suffer an “Oops”? This problem is the sort Civil Engineers face when trying to decide how many soil samples to collect to assure the foundation design will be sufficient and most economical. This sort of problem is faced at every level in project planning: “How much effort is it worth to assure weekly work plan is 100% planning reliable? At what level of precision – week, day, hour, minute?” It is unlikely that anyone on the project could answer such a question because there are so many possible immediate and longer-term interactions with unknown consequences. This simple 9-card simulation can be used in research and teaching to study the cost and benefits of planning under uncertainty both in “economic” and human decision making terms. At the extreme, there are two strategies in Oops Game: 1) No planning, the “Guts Ball” approach where the cost of planning is lowest and risk of an “Oops” is highest; and 2) Risk averse where the investment is made in planning until there is no risk of an “Oops.” In a third and more realistic approach, “Judgment” the decision to plan rests on an analysis the risks and likely outcomes in the situation at hand. The paper explains the simulation and its application in the classroom and as a platform for research into planning effectiveness, decision-making, and complexity.


Lean construction, planning, risk, project management, productivity, reliability.



Howell, G. & Liu, M. 2012, 'The Oops Game: How Much Planning Is Enough?' In:, Tommelein, I.D. & Pasquire, C.L., 20th Annual Conference of the International Group for Lean Construction. San Diego, USA, 18-20 Jul 2012.

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