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INTRODUCING THE THEORY

OF CONSTRAINTS

John F. DeVogt, Ph.D.

Professor of Management Emeritus

Williams School of Commerce

Washington and Lee University

Lexington, Virginia

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ABOUT TOC

TOC applies the methods used by the

hard sciences to understand and manage

the material world of human-based systems

including the lives of individuals and

organizations.

TOC comprises a methodology for solvingproblems and implementing the solution

found.

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A B

Which System is

More Complex?

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WHAT IS THE

DEF

INITION OF

APROBLEM?

The traditional definition of a problem is a

source of perplexity, distress or irritation.

The TOC/hard science definition of a

problem is a conflict between two

conditions/observations. (A basic belief in

science is that conflicts do not exist in

reality; i.e., something is wrong in our

understanding.)

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THE THINKING

PROCE

SSE

S (TP) OF

TOC

Tools that enable us to use logic to gain an

understanding of our reality and then to find

ways of improving it.

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BASIC CONSTRUCTS

OF THE TOC TP

Causality: Ifthen

Necessity: In order toI must

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EXAMPLE OF

CAUSALITY IFTHEN

I get

burned.

I touch ahot stove.

I don't getburned

I touch a

hot stove

I amwearing an

oven mitt.

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EXAMPLE OF

NECESSITY In order toI must

Avoid getting

burned.

Do not touch a

hot stove.

Touching a hot stove willburn me.

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PROCESS OF

ONGOINGIMPROVEMENT

No matter what the subject matter,

accelerated improvement involves

answering the following questions

What to change?

To what to change?

How to cause a change?

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ANSWERING THE

QUESTIONS

What to change? Identify the core conflict

or problem (the constraint).

To what to change? Construct a complete

solution.

How to cause a change? Devise plans for

implementing the solution and achieving

buy-in where necessary.

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EMPLOYING THE

TP IN ANSWE

RINGTHE QUESTIONS

What to change? Generic cloud processor Current Reality Tree.

To what to change? Evaporating Cloud,

Future Reality Tree, Negative BranchReservations.

How to cause a change? Pre-Requisite

Tree, Transition Tree, TOC Buy-In.

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TOOL-TYPES OF THE

TP Necessity:

Generic Cloud

Process

Evaporating Cloud

(EC)

Pre-Requisite Tree

(PRT)

Causality:

Current Reality Tree

(CRT) Future Reality Tree

(FRT)

Negative Branch

Reservation (NBR) Transition Tree (TrT)

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WHAT TO CHANGE?

Both the CRT and the Generic Cloud

Process permit us to state the current

situation as a conflict that must be resolved

if that situation is to be improved.

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The EC

Representation of

the Conflict

A

The Objective

BOne Requirement

For A

DOne Requirement

For B

C

One Requirement

For A

D

One Requirement

For C

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WHAT TO CHANGE

TO? Uncover and challenge the assumptions

underlying the EC structure.

Find an injection (change in reality) that

effectively destroys an assumption behind

an arrow in the EC.

Build a FRT from that injection.

Subject the FRT to Negative Branch

Reservations.

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HOW TO CAUSE THE

CHANGE? The amended FRT will contain more than

one injection. For each of these injections, a

PRT will answer the question: what

currently prohibits its implementation?

Each PRT requires actions and these are

devised through one or more TrTs.

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TOC APPLIED TO

BUSINE

SSORGANIZATIONS

Acknowledging and managing the

interdependencies that exist within anorganization and among organizations and

their effect on flow throughout the entire

supply chain.

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COST WORLD VIEW vs. THROUGHPUT

WORLD VIEW

Prime measurement:

WEIGHT

Any improvement of any

link is an improvement of

the chain.

Global improvement =sum of local

improvements.

Prime measurement:

STRENGTH

Most improvements of

most links do not improve

the chain.

Global improvement =improvement in the

constraint(s).

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THROUGHPUT WORLD

VIEW (Strength) Suppliers, Vendors Functions, Departments, etc. Customers, markets

PULL

FLOW

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