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Goldratts Thinking Process and Systems Thinking

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Title: Goldratts Thinking Process and Systems Thinking


1
Goldratts Thinking Process and Systems Thinking
  • James R. Burns
  • Nov. 13, 2008

2
THEORY OF CONSTRAINTS GOLDRATT
  • 1. Identify the system constraint(s)
  • 2. Decide how to exploit the system constraints
  • 3. Subordinate everything else to that decision
  • 4. Elevate the system constraint(s)
  • 5. When this creates new constraints, go back to
    step 1

3
Reference(s)
  • Dettmer, H. William, Goldratts Theory of
    Constraints, ASQ, 1997.

4
THE ISSUES ARE
  • What to change?
  • What is the core problem?
  • What to change to?
  • Where to look for the breakthrough idea?
  • How to effect the change?
  • How to bridge from a breakthrough idea to a full
    solution?

5
THE TOOLS ARE
  • What to change?
  • Here we use a current reality tree
  • What to change to?
  • Here we use an evaporating cloud and a future
    reality tree
  • How to effect the change?
  • Here we use a prerequisite tree and a transition
    tree

6
Goldratts TP (Thinking Process)
  • An excellent methodology to facilitate sessions
    during the initiation phase (definition and
    conceptualization stage) of a project

7
Strategy for change
  • Create the tree
  • Critique the tree

8
Why trees??
  • To get a complete picture of what is going on
  • To model all of the causation involved
  • To see what is related to what
  • To identify the core problem
  • To validate a proposed injection

9
What to change?
  • Team constructs a current reality tree (CRT)
  • Team starts by listing all undesirable effects
    (UDEs)
  • Team inter-relates these by use of a tree, called
    a CRT
  • In the current reality tree, the team traces
    UDEs back to a core problem (CP)

10
EXAMPLES OF UDEs
  • Due dates are often missed
  • It is difficult to respond to urgent demands
  • There are too many late-breaking changes to
    requirements
  • Required human resource levels are too low
  • There are frequent schedule overruns
  • Budgets are often exceeded

11
Example Current Reality Tree
Managing Software Development Projects Is rarely
successful
Software Development Projects take too long
Software Development Projects cost too much
Software Development Projects have
quality problems
12
Software Development Projects take too long
Software Development Projects cost too much
Fixing changes takes time
There are many late- breaking changes to
requirements
Fixing changes costs money
13
There are many late- breaking changes to
requirements
The technology is changing rapidly
Users do not know what They want
There is much un- discovered work
Change in the business World is rampant
14
NEXT QUESTION What to Change to??
  • Evaporating Cloud
  • Future Reality tree

15
Core problems are studied further by use of an
evaporating cloud
  • Evaporating clouds (EC) will surface assumptions
  • Breaking an assumption leads to a breakthrough
    called an injection
  • At this point the team is unconcerned with the
    practicality of the injection

16
What is an injection?
  • a solution to the core problem
  • a strategy that will mitigate all of the UDEs
  • Injections that appear impossible to achieve are
    called

Flying pigs
17
Future Reality Tree
  • From the CRT and ECs, a Future Reality Tree (FRT)
    is constructed
  • One purpose of the Future Reality Tree is to
    validate that the injection will achieve the
    desired effects (DEs)

18
Examples of UDEs and DEs
  • Due dates are rarely missed
  • Demands are met 99 of the time
  • There is little expediting
  • Inventory levels are low
  • There are no material shortages
  • Production lead times are short or satisfactory
  • Due date perf. is high
  • Customers rely on quick responses
  • There is little expediting
  • Inventory levels are reduced significantly
  • Material is available when needed
  • Customers rely on quick responses

19
Building the Future Reality Tree
  • Start by turning the UDEs around and writing
    them with a positive tone as DEs
  • Place DEs at the top of the limbs in the FRT
  • At the bottom of the FRT place the injection
  • Building the FRT is a two-phase process
  • Build considering only positive, ideal links, and
    assuming win/win strategies
  • Add negative loops later

20
What to change to, Contd?
  • The idea here is to get a picture of how an
    injection (a breakthrough) might affect the
    overall performance of the system.
  • The Future Reality Tree is the validation that a
    collection of injections will turn all of the
    UDEs into DEs

21
How to cause the change?
  • The prerequisite tree
  • The transition tree
  • These help to get buy-in
  • These help us to develop a strategy for achieving
    a flying pig (an injection that appears
    impossible to achieve or implement)

22
The Prerequisite Tree
  • Place INJECTIONS at the top
  • List the obstacles that are expected
  • For each obstacle that is overcome, an
    intermediate objective is achieved
  • Each obstacle gives rise to an intermediate
    objective
  • The intermediate objectives need to be sequenced

23
The Prerequisite Tree, Contd
  • Takes an impediment or obstacle approach
  • This approach enables dissection of the
    implementation task into an array of
    interrelated, well-defined, intermediate
    objectives

24
The Transition Tree
  • We know where we stand
  • We identified the core problem
  • We found an injection (one or more) that produces
    the desired effects
  • We found the milestones of the journey--the
    intermediate objectives (IOs)
  • The question now is What specific actions must we
    take?

25
The Transition Tree, Contd
  • We must focus, not on what we plan to do but on
    what we plan to accomplish
  • For each IO, a specific action or set of actions
    are determined and initiated
  • Causing a specific change in reality is the
    imperative
  • The transition tree provides a ROAD MAP for
    getting from here to there!

26
Thats it for GCT
  • To get the full version, you have to go to New
    Hampshire (Goldratt Institute) , spend two weeks
    and 10,000

27
Let's Transition to Systems Thinking
28
Systems Thinking vs. Goldratt Thinking Process
  • System Thinking is good for dynamical situations
  • Goldratt is good for surfacing underlying
    beliefs, assumptions that are incorrect
  • There is some overlap between the two
    methodologies

29
Why systems thinking?
  • Because our logical deduction mechanisms are
    trained to induct linearly, not cyclically
  • We dont see the feedback loops
  • Consequently, we dont comprehend the
    opportunities for reinforcement or the
    consequences of limitations/constraints
  • Forrester every decision, every action is
    embedded in an information feedback loop

30
More motivation
  • We are immersed in and victims of structures that
    we have little awareness of
  • Causes and their effects are often spatially and
    temporally separated
  • Todays problems are yesterdays solutions
  • To make good decisions we need to understand
    dynamic complexity, not detail complexity

31
Still more motivation
  • The integration that comes from the application
    of information technology is creating complexity
    at a frenetic pace
  • Out of the complexity comes the potential for
    chaos and catastrophe
  • To understand and cope with the complexity
    requires causal models provided by systems
    thinking

32
Key Benefits of the ST
  • A deeper level of learning
  • Far better than a mere verbal description
  • A clear structural representation of the problem
    or process
  • A way to extract the behavioral implications from
    the structure and data
  • A hands on tool on which to conduct WHAT IF

33
Senges Five Disciplines
  • Personal Mastery
  • because we need to be the very best we can be
  • Mental Models
  • because these are the basis of all
    decision-making
  • Shared Vision
  • because this galvanizes workers to pursue a
    common goal
  • Team Learning
  • because companies are organized into teams
  • Systems Thinking
  • because this is only tool for coping with
    complexity

34
We are creating a language
  • reinforcing feedback and balancing feedback are
    like the nouns and verbs
  • systems archetypes are the basic sentences
  • Behavior patterns appear again in all
    disciplines--biology, psychology, family therapy,
    economics, political science, ecology and
    management
  • Can result in the unification of knowledge across
    all fields

35
Recurring behavior patterns
  • Do we know how to recognize them?
  • Do we know how to describe them?
  • Do we know how to prescribe cures for them?
  • The ARCHETYPES describe these recurring behavior
    patterns

36
The ARCHETYPES
  • Provide leverage points, intervention junctures
    at which substantial change can be brought about
  • Put the systems perspective into practice
  • About a dozen systems ARCHETYPES have been
    identified
  • All ARCHETYPES are made up of the systems
    building blocks reinforcing processes,
    balancing processes, delays

37
Before looking at the ARCHETYPES we need to
understand simple structures
  • The reinforcing feedback loop
  • Exhibits exponential growth behavior
  • The balancing feedback loop
  • Exhibits goal-seeking behavior

38
ARCHETYPE 1 LIMITS TO GROWTH
  • A reinforcing process is set in motion to produce
    a desired result. It creates a spiral of success
    but also creates inadvertent secondary effects
    (manifested in a balancing process) that
    eventually slow down the success.
  • All growth will eventually run up against
    constraints, impediments

39
Management Principle relative to ARCHETYPE 1
  • Dont push growth or success remove the factors
    limiting growth
  • This is equivalent to Goldratts Theory of
    Constraints

40
Reinforcing Loop Structure
41
Reinforcing Loop Behavior
42
Balancing Loop Structure
43
Balancing Loop Behavior
44
ARCHETYPE 1 LIMITS TO GROWTH
  • Useful in all situations where growth bumps up
    against limits
  • Firms grow for a while, then plateau
  • Individuals get better for a while, then their
    personal growth slows.

45
Structure
growing action
state of stock
slowing action
Balancing
Reinforcing
46
Understanding the Structure
  • High-tech orgs grow rapidly because of their
    ability to introduce new products
  • This growth plateaus as lead times become too
    long for development of enhancements to existing
    products
  • have you considered what happens as software
    becomes more complex???

47
How to achieve Leverage
  • Most managers react to the slowing growth by
    pushing harder on the reinforcing loop
  • Unfortunately, the more vigorously you push the
    familiar levels, the more strongly the balancing
    process resists, and the more futile your efforts
    become.

48
Leverage, Continued
  • Instead, concentrate on the balancing
    loop--changing the limiting factor
  • This is akin to Goldratts Theory of
    Constraints--remove the bottleneck, the
    impediment, the

Constraint!!
49
Applications to Quality Circles and JIT
  • Quality circles work best when there is
    even-handed emphasis on both balancing and
    reinforcing loops
  • THERE WILL ALWAYS BE MORE LIMITING PROCESSES
  • When one limitation or impediment is removed,
    another will surface
  • Growth eventually WILL STOP

50
Create your own LIMITS TO GROWTH story
  • Identify a limits to growth pattern in your own
    experience
  • Diagram it
  • What is growing
  • What might be limitations
  • Example--the COBA and University capital
    campaigns
  • NOW, LOOK FOR LEVERAGE

51
Test your LIMITS TO GROWTH model
  • Talk to others about your perception
  • Test your ideas about leverage in small real-life
    experiments
  • Run and re-run the simulation model
  • Approach possible resistance and seek WIN-WIN
    strategies with them

52
ARCHETYPE 2 shifting the burden
  • An underlying problem generates symptoms that
    demand attention. But the underlying problem is
    difficult for people to address, either because
    it is obscure or costly to confront. So people
    shift the burden of their problem to other
    solutions--well-intentioned, easy fixes that seem
    extremely efficient. Unfortunately the easier
    solutions only alleviate the symptoms they leave
    the underlying problem unaltered. The underlying
    problem grows worse and the system loses whatever
    abilities it had to solve the underlying problem.

53
The Stereotype Structure
Symptom-Correcting Process
Addiction Loop
Problem-Correcting Process
54
EXAMPLE
55
Another Example
Raise tuition, add course fees, etc.
Costs of Higher Ed not funded by State
Perceived cost to the student
Lower enrollments
56
Still Another Example
Symptom-correcting process
Addiction Loop
Problem-correcting Process
57
Shifting the Burden is an insidious problem
  • Is has a subtle reinforcing cycle
  • This increases dependence on the symptomatic
    solution
  • But eventually, the system loses the ability to
    apply the fundamental solution
  • The system collapses

58
Senge Says
  • Todays problems are yesterdays solutions
  • We tend to look for solutions where they are
    easiest to find

59
HOW TO ACHIEVE LEVERAGE
  • Must strengthen the fundamental response
  • Requires a long-term orientation and a shared
    vision
  • Must weaken the symptomatic response
  • Requires a willingness to tell the truth about
    these solutions

60
Create your own Shifting the Burden Story
  • Is there a problem that is getting gradually
    worse over the long term?
  • Is the overall health of the system gradually
    worsening?
  • Is there a growing feeling of helplessness?
  • Have short-term fixes been applied?
  • The Casa Olay problem of using coupons to
    generate business and then cant get away from
    using the coupons because their customer base is
    hooked on coupons

61
To structure your problem
  • Identify the problem
  • Next, identify a fundamental solution
  • Then, identify one or several symptomatic
    solutions
  • Finally, identify the possible negative side
    effects of the symptomatic solution

62
Special Case Eroding Goals
  • Full employment meant 4 unemployment in the
    1960s, but 6 to 7 unemployment in the early
    1980s
  • Gramm-Rudman bill called for reaching a balanced
    budget by 1991, but this was shifted to 1993 and
    from 1993 to 1996 and from 1995 to 1997
  • If all else fails, lower your goals..

63
Another Archetype Eroding Goals
  • A type of structure in which the short-term
    solution involves letting a long-term,
    fundamental goal decline
  • MANAGEMENT PRINCIPLE Hold the vision
  • Dont lower your goals, your standards, your
    vision

64
Structure
65
Leadership according to Senge
  • Articulate the GOAL
  • Articulate the actual CONDITION
  • Use the GAP between the two to pull the actual
    CONDITION toward the GOAL
  • CALLED CREATIVE TENSION the idea is to make
    visible the GAP so that everyone will try harder
    to reach the un-compromised GOAL

66
Review
  • We have now seen two of the basic systems
    archetypes.
  • The Limits to Growth Archetype
  • The Shifting the Burden Archetype
  • As the archetypes are mastered, they become
    combined into more elaborate systemic
    descriptions.
  • The basic sentences become parts of paragraphs
  • The simple stories become integrated into more
    involved stories

67
The Saga of Peoples Air
  • A totally different airline
  • Founded in 1980 to provide low-cost, high-quality
    airline service to travelers in the Eastern U.S.
  • Grew to nations 5th largest carrier
  • Brought in a host of innovative human resource
    policies
  • In 1986 lost 133M in first six months, and was
    taken over by Texas Air

68
What brought PEOPLES down??
  • Many explanations
  • Some blame Burrs soft people-oriented
    management policies
  • Some blamed the unions
  • Others blamed the use of Americans Sabre
    Reservation system
  • Load management could offer a limited number of
    low-cost seats while others were full coach

69
What variables to blame?
  • Fleet variables
  • Human resource variables
  • Competitive factors
  • Financial variables
  • Policy Levers

70
Fleet variables
  • Planes
  • Capacity of aircraft
  • Routes
  • Scheduled flights
  • Competitor routes
  • Service hours per plane per day
  • Fuel efficiency

71
Human resources
  • Service personnel
  • Aircraft personnel
  • Maintenance personnel
  • Hiring
  • Training
  • Turnover
  • Morale
  • Productivity
  • Experience
  • Team management
  • Job rotation
  • Stock ownership
  • Temporaries

72
Competitive Factors
  • Market size
  • Market segments
  • Reputation
  • Service quality
  • Competitor service quality
  • Fares load Management
  • Competitor fares

73
Financial variables
  • Revenues
  • Profit
  • Cost of plane operations
  • Cost of service operations
  • Cost of marketing
  • Wages
  • Stock price
  • Growth rate
  • Debt
  • Interest Rate

74
Policy Levers
  • Buying planes
  • Hiring people
  • Pricing
  • Marketing expenditures
  • Service scope

75
Enormous detail complexity
  • We could build a model that contained all of this
    detail
  • Or we could use the systems archetypes to
    disentangle this parable of complexity

76
What do we have in terms of loops?
  • A growth loop certainly (reinforcing)
  • The airline, unlike WonderTech was investing in
    its capital equipment infrastructure
  • It was buying planes to accommodate the growth
  • A balancing loop

77
What archetypes?
  • LIMITS TO GROWTH
  • ERODING GOALS (standards)
  • The combination of these produces a third
    archetype
  • The Growth and Under-investment Archetype
  • This was first seen in the WonderTech Scenario

78
The Simplified Structure--p. 133
79
The Simulation Structure--Reinforcing Loop
80
The Simulation
81
System Dynamics (SD) Basics
  • Peruse relevant literature
  • Talk to people knowledgeable about the problem
  • List relevant variables
  • Describe causal interactions between variables
  • Fully delineate the causal loop diagram (CLD)
  • Draw behavior over time graphs

82
More SD Basics
  • From the CLD, delineate the Stock and Flow
    Diagram (SFD)
  • From the SFD, enter into Vensim and run the
    simulation model
  • Conduct WHAT IF experiments on the simulation
    model within Vensim.
  • Draw conclusions and determine policy
    recommendations

83
Examples
  • Itch--scratch
  • population and growth rate of population
  • revenues, sales force size, sales
  • inventory, order rate, desired inventory,
    adjustment time

84
What is system dynamics?
  • A way to characterize systems as stocks and flows
    between stocks
  • Stocks are variables that accumulate the affects
    of other variables
  • Rates are variables the control the flows of
    material into and out of stocks
  • Auxiliaries are variables the modify information
    as it is passed from stocks to rates

85
A single-sector Exponential growth Model
  • Consider a simple population with infinite
    resources--food, water, air, etc. Given,
    mortality information in terms of birth and death
    rates, what is this population likely to grow to
    by a certain time?

86
Exponentially growing population model
  • In 1900 there were just 1.65 billion people on
    the planet. Today, there are more than 6 billion
    people on the planet. Every year there are .04
    births per capita and .028 deaths per capita.
  • The .04 births per capita shall be referred to as
    a parameter called BIRTH RATE NORMAL

87
From Causal Diagram to Schematic (Stock Flow)
Diagram (SFD)
  • Some simple causal models
  • Some associated schematic models
  • Some rules

88
Some rules for translating CLDs into SFDs
  • What we are doing is identifying every connection
    (also called edge or arrow) and every quantity in
    the CLD as to type

89
Linkage (Edge) Types
  • There are two types of causal links in causal
    models
  • Information
  • Flow
  • Information proceeds from stocks and parameters
    toward rates where it is used to control flows
  • Flow edges proceed from rates to states (stocks)
    in the causal diagram always

90
Loops
  • In any loop involving a pair of quantities/edges,
  • one quantity must be a rate
  • the other a state or stock,
  • one edge must be a flow edge
  • the other an information edge

91
CONSISTENCYa way to identify connections and
quantities
  • All of the edges directed toward a quantity are
    of the same type
  • All of the edges directed away from a quantity
    are of the same type

92
Rates and their edges
93
Parameters and their edges
94
Stocks and their edges
95
Auxiliaries and their edges
96
Outputs and their edges
97
Steps for Translating CLDs into SFDs
98
STEP 1 Identify parameters
  • Parameters have no edges directed toward them

99
STEP 2 Identify the edges directed from
parameters
  • These are information edges always

100
STEP 3 By consistency identify as many other
edge types as you can
101
STEP 4 Look for loops involving a pair of
quantities only
  • Use the rules identified above

102
System Dynamics Software
  • STELLA and I think
  • High Performance Systems, Inc.
  • best fit for K-12 education

103
Vensim More System Dynamics Software
  • Ventana systems, Inc.
  • Free from downloading off their web site
    www.vensim.com
  • Robust--including parametric data fitting and
    optimization
  • best fit for higher education

104
Powersim Yet another
  • What Accenture is using
  • More like STELLA

105
A DEMO
106
Can you construct the schematic model for this
Causal model?
107
We know what that is
108
How about this one?
109
We know what it is, as well
110
Seeing Structures, not just Trees
  • Helps us focus on what is important and what is
    not
  • Helps us determine what variables to focus on and
    which to play less attention to

111
WonderTech The Chapter 7 Scenario
  • A lesson in Growth and Underinvestment
  • What Senge gets out of this is the Growth and
    Underinvestment Archetype
  • A combination of variants of the Limits to Growth
    Archetype and the Shifting the Burden Archetype

112
The WonderTech Scenario
  • WonderTech continues to invest in the growth side
    of the process. Sales grow but then plateau.
    Management puts more sales people into the field.
    Offers more incentives to sales force. But
    because of long lead times, customers wane. Yes
    you have a great product, but you cant deliver
    on your lead time promise of eight weeks. We
    know weve heard from your other customers.
    In fact, the company relaxed its lead-time
    standard out to twelve to sixteen weeks because
    of insufficient capacity.

113
The Reinforcing Loop
114
The Balancing Loop Following the LTG Archetype
115
The Growth Curve Page 117
116
Whats happened?
  • WTs management did not pay much attention to
    their delivery service. They mainly tracked
    sales, profits, market share and return on
    investment. WTs managers waited until demand
    fell off before getting concerned about delivery
    times. But this is too late. The slow delivery
    time has already begun to correct itself. The
    management was not very concerned about the
    relaxed delivery time standard of eight weeks.

117
The WonderTech Scenario
  • The firm decides to build a new manufacturing
    facility. But the facility comes on line at a
    time when sales are declining and lead times are
    coming back to the eight-week standard.
  • Of every 10 startup companies, 5 will disappear
    with five years, only 4 survive into their tenth
    year and only 3 into their fifteenth year.

118
The Shifting the Burden Component
119
Put the whole thing together
120
Comments on The Senge Methodology
  • Sees problems as conforming to a finite number of
    archetypes
  • Formulates models based on combinations of the
    archetypes
  • Addresses problem-driven situations
  • What about situations and systems that are
    technology-driven, dynamics-driven,
    exogenously-driven, anything but problem-driven

121
More Comments on the Senge Methodology
  • But does this become sufficiently general to
    accommodate all dynamical scenarios and
    situations?
  • It is difficult to translate his archetypes and
    causal models into running system dynamics
    simulations
  • A lot of variables (RATE VARIABLES, specifically)
    get left out in terms of connections

122
More Comments on the Senge Methodology
  • The focus is on characterizing the dynamics, not
    on how to capture that in terms of stocks, flows
    and information paths
  • He doesnt label his edges with or - signs

123
Another methodology The Sector Approach to SD
model formulation
  • Begin by identifying the sectors
  • A sector is all the structure associated with a
    single flow
  • There could be several states in a single sector
  • Determine the within-sector structure
  • Reuse existing molecules where possible
  • Determine the between-sector information
    infrastructure
  • There are no flows and therefore no stocks or
    rates here

124
A Single-sector Exponential goal-seeking Model
  • Sonya Magnova is a television retailer who wishes
    to maintain a desired inventory of DI television
    sets so that she doesnt have to sell her
    demonstrator and show models. Sonyas ordering
    policy is quite simple--adjust actual inventory I
    toward desired inventory DI so as to force these
    to conform as closely as possible. The initial
    inventory is Io. The time required for ordered
    inventory to be received is AT.

125
A Two-sector Housing/population Model
  • A resort community in Colorado has determined
    that population growth in the area depends on the
    availability of hoousing as well as the
    persistent natural attractiveness of the area.
    Abundant housing attracts people at a greater
    rate than under normal conditions. The opposite
    is true when housing is tight. Area Residents
    also leave the community at a certain rate due
    primarily to the availability of housing.

126
Two-sector Population/housing Model, Continued
  • The housing construction industry, on the other
    hand, fluctuates depending on the land
    availability and housing desires. Abundant
    housing cuts back the construction of houses
    while the opposite is true when the housing
    situation is tight. Also, as land for
    residential development fills up (in this
    mountain valley), the construction rate decreases
    to the level of the demolition rate of houses.

127
What are the main sectors and how do these
interact?
  • Population
  • Housing

128
What is the structure within each sector?
  • Determine state/rate interactions first
  • Determine necessary supporting infrastructure
  • PARAMETERS
  • AUXILIARIES

129
What does the structure within the population
sector look like?
  • RATES in-migration, out-migration, net death
    rate
  • STATES population
  • PARAMETERS in-migration normal, out-migration
    normal, net death-rate normal

130
What does the structure within the housing sector
look like?
  • RATES construction rate, demolition rate
  • STATES housing
  • AUXILIARIES Land availability multiplier, land
    fraction occupied
  • PARAMETERS normal housing construction, average
    lifetime of housing
  • PARAMETERS land occupied by each unit, total
    residential land

131
What is the structure between sectors?
  • There are only AUXILIARIES, PARAMETERS, INPUTS
    and OUTPUTS

132
What are the between-sector auxiliaries?
  • Housing desired
  • Housing ratio
  • Housing construction multiplier
  • Attractiveness for in-migration multiplier
  • PARAMETER Housing units required per person

133
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