Time and Requisite Variety:Lessons from Project Management

Frank T. Anbari and Stuart A. UmplebyThe George Washington University

Washington, DC

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The law of requisite variety

• First described by W. Ross Ashby in 1952

• Similar to game theory – have a move to counter every possible move by an opponent

• Time is a separate dimension not included when calculating variety

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First version

• The amount of selection that can be performed is limited by the amount of information available

• Example: Admitting students to college• What if there are five students and

information on only three?• “When all available information has been

exhausted, do whatever you like.”

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Second version

• The variety in the regulator must be at least as great as the variety in the system being regulated

• Example: Buy a computer with a capacity not less than the required task

• Example: In sports have a defense for every offense and seek to create novel offenses

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Implication for management

• When confronted with a task more complicated than one can cope with, there are two and only two choices

• One: Increase the variety in the regulator (for example by hiring more staff)

• Two: Reduce the variety in the system being regulated

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Implementing the second strategy

• The second strategy is surprisingly powerful

• Reducing the variety in the system being regulated is possible because a system is “a set of variables defined by the observer”

• That is, one can redefine the system so that it is manageable

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Projects and Programs

• “A project is a temporary endeavor undertaken to create a unique product, service, or result…Most projects are undertaken to create a lasting outcome.”

• “A program is a group of related projects managed in a coordinated way to obtain benefits and control not available from managing them individually.”

Project Management Institute (2004)

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Rich, Long History ofProject Management (PM)

• The Wheel• The Pyramids• The Great Walls of China• Roads, viaducts, Canals, and architecture• Defense systems• Computers and telecommunications• Medical and pharmaceutical projects• Space exploration and utilization

Continued…Sources: Cleland, David I. The Societal Contribution of Project Management, IPMA 17 th World Congress on Project Management, Moscow, Russia June 4-6, 2003, and Anbari, F.T. & Romanova, M.V. Developing Competitive Organizations trough Six Sigma, Innovation, and Project Management, EURO / INFORMS Joint International Meeting, Istanbul, Turkey, July 6-10, 2003.

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Projects and Project Management

• A project can be defined as a system that transforms inputs into outputs and has a feedback mechanism: The system to be regulated

• The PM system (including the project manager and team) can be defined as: The regulator

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PhysicalHumanConceptual

IntegrationScopeTimeCostQualityHuman ResourcesCommunicationsProcurementRisk

PhysicalConceptual

FEEDBACK

ScopeTimeCostQuality

INPUT PROCESS OUTPUT

A Systems Approach to Project Management

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Projects as Systems

• Projects are Complex systems• May have a single or often multiple objectives• The objectives may have different priorities• Highly constrained usually with multiple

constraints• Some objectives may also act as constraints• Systems dynamics and interventions by key

stakeholders increase complexity of the project management system

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Project objectives and constraints

• Time and cost have traditionally been considered as the main constraints on projects

• The triple constraint theory adds a third constraint (often called performance)

• Scope, time, cost, and quality have been proposed as the quadruple objectives and constraints

• Risk tolerance and resource availability may be added as constraints only

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Quadruple Objectives / Constraints of Project Management

Scope

Quality

Cost

Time

With proper prioritization of project objectives

F. T. Anbari, 1985, 2005

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TimeTime CostCost

FirstFirst

SecondSecond

ThirdThird

ScopeScope QualityQuality

Prioritization of objectives: Example

Priority

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Time and requisite variety

• Previously in discussions of requisite variety, time was not considered because it was thought to be a different kind of variable

• In the game theoretical formulation, requisite variety lists capabilities, which are executed in time

• However, time is itself a capability or is a way to increase capability

• This is a notion that was excluded in the original, formal, game theoretical interpretation of requisite variety

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Time in project management• In managing projects, time is usually considered to

be a critical (trade-off) variable:– Taking more time often allows projects to be completed

to satisfy other project objectives– The time constraint often affects the achievement of

other project objectives

• The common practice of "extending time" in project management calls attention to the formal interpretation of time in the cybernetics literature

• A broader interpretation of time can bring cybernetics closer to other fields

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The Correspondence Principle

• Proposed by Niels Bohr when developing quantum theory

• Any new theory should reduce to the old theory to which it corresponds for those cases in which the old theory is known to hold

• A new dimension is required

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“New” Law of requisite variety         

An Application of the Correspondence Principle 

Law of requisite variety

Time variable

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The law of requisite variety and project management

• The law of requisite variety can make important contributions to PM, since the PM system (or process) approach is becoming very widely accepted in PM

• PM can make an interesting contribution to cybernetics and the law of requisite variety by appropriately addressing the time variable

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Cybernetics and behavioral science

• An advantage of cybernetics is that it sometimes lends itself to mathematical analysis, similar to game theory

• Most of behavioral science is not expressed as axiomatic theories:– Behavior occurs in time

• Including time with requisite variety may lead to analyses closer to behavioral science

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References• Anbari, F. T. (1985). “A Systems Approach to Project Evaluation,” Project Management Journal,

Vol. XVI, No. 3, pp. 21 – 26.

• Anbari, F. T. (2005). Innovation, Project Management, and Six Sigma Method. Current Topics in Management, Vol. 10, pp. 101-116, New Brunswick, NJ: Transaction Publishers

• Ashby, W. R. (1952). Design for a Brain: The Origin of Adaptive Behavior. London: Chapman and Hall.

• Ashby, W. R. (1957). An Introduction to Cybernetics. London: Chapman and Hall.

• Checkland, P. (2000). Soft Systems Methodology: A Thirty Year Retrospective. Systems Research and Behavioral Science, Vol. 17, Iss. S1, pp. S11 – S58.

• Schwaninger, M. (2004). What can cybernetics contribute to the conscious evolution of organizations and society? Systems Research and Behavioral Science, Vol. 21, Iss. 5, pp. 515 – 527.

• Project Management Institute. (2004). A guide to the project management body of knowledge, (3rd ed.). Newtown Square, PA: Author.

• Umpleby, S.A. (2004). “Strategies for Regulating the Global Economy.” Cybernetics and Systems. Retrieved on October 22, 2005 from http://www.gwu.edu/~umpleby/recent_papers/st_regulating.htm

• Umpleby, S. A. (2002). Should Knowledge of Management Be Organized as Theories or as Methods? The George Washington University. Retrieved on July 28, 2005 from http://www.gwu.edu/~umpleby/recent_papers/2002_knowledge_of_management_organized_as_theories_or_as_methods.htm