Wednesday, February 01, 2012


On Decision-Making

There is a prior step to good decision-making:  Problem Analysis

In my view there are quite a number of drivers for making decisions.

Here is a partial list, in no special order:

--Rational and analytical

--Dictated by:

   A person in charge, by careful thought or whim


   Political ideology

   Laws, such as the Constitution




   Emotions of a mob


--Haphazard, as in letting things happen

--Deliberate non-decision-making

--Irrational decision-making




   Tea leaves



   Mean of a distribution

   Median of a distribution

   Throw of the dice

   Toss of a coin

Rational/analytical decision-making is a preferred process since it minimizes the inclusion of extraneous or nebulous elements and constraints on the eventual solution.

A distinction should be made between decision-making and problem analysis. In fact, several things must happen before a rational decision can be made:

Problem Analysis

1) Objective and scope: Determine the objective of the decision, the scope of the problem and the universe of possible solutions, being careful to define the constraints to be imposed on the solutions. Take into account prior solutions to the same or a similar problem.

2) Problem Analysis: Analyze the problem, being certain to include all known factors affecting the objective within the scope of possible solutions. Establish the needs and requirements for the solution.

3) Possible Solutions: Identify all major practical solutions possible within the constraints.


1. Perform tradeoff studies between the alternative solutions to decide which solution or solutions meet the needs.

2. Decide upon and select the most promising solutions for further analysis and tradeoff studies.

3. Decide to prototype the selected solutions for further evaluation. Halt the process if infeasible.

4. Decide and select the final solution.

Example: Perhaps a very simplified example will clarify these steps:

Problem Analysis

Objective and scope: to carry 400 passengers in comfort to any point on the globe within 10 hours.

Prior solutions: Boeing 747, 20 to 24 hours, and one stop for refueling. B-2 Bomber flying wing, which requires multiple in-air refuelings to extend its range.

Possible Solutions: The only practical solution at this time is to design a better commercial transport plane, and more efficient engines. Configuration possibilities are basically twofold: 1) a conventional aerodynamic design; and, 2) a more efficient aerodynamic design, such as a flying wing. Current jet engines cannot achieve the fuel economy needed for over Mach 1 flight for 15 thousand miles, which means a new state of the art engine development is necessary. In-air refueling is not to be considered. Consideration of the impact on ground handling must be factored into the analysis.

Passenger comfort and a pleasing experience is a heavy constraint.


Decide between conventional and unconventional aerodynamic configurations by modeling and wind tunnel analysis, followed by a possible prototyping flyoff between competitive designs using available engines. Decide whether small scale models of the airframes would suffice to decide between the two configurations, or should the two airframes be built full scale.

Decide between feasible competitive engine designs through analysis of competing designs, and possibly a run-off test between prototypes. Constraints here include meeting the installation requirements of the airframes under consideration. (If no feasible engine design is forthcoming, the problem is over.)
Decide between competitive proposals from aircraft builders for the prototype developments.

Decide whether to extend the competition to include more than one airframe and engine selection, or to go ahead with detailed design, development, test and pre-production prototyping of only a single solution.

Decide the final solution, in this case, say, a four-engine 400 seat conventional configuration. This was decided basically on the needs for ground handling at terminals and the width of the wings, and (partially, shall we say) on the criteria for passenger comfort and a pleasing experience, since the wing configuration does not allow for as adequate a passenger viewing experience as does the conventional design.



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