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ESD.36 System Project Management
Instructor(s)
+
- The Rework Cycle
Dr. James Lyneis
Lecture 7
Copyright © 2012 James M Lyneis.
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2
Today’s Agenda
Overview: Causes of Project Dynamics
The Rework Cycle
Integrating Tools in Project Planning
Simple Model of Project Dynamics, Pt. 1
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- Typical Behavior Modes on a Project
3
ProjectStaffing
Time
TypicalPlan
Productivity(Normalised)
Time
1
2TypicalPlan
© 2001 John Wiley & Sons, Ltd. All rights reserved. This content is excluded from ourCreative Commons license. For more information, see http://ocw.mit.edu/fairuse.
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4
Drivers of Project Dynamics
The “rework cycle”
Feedback effects
Negative, controlling
Positive, re-enforcing, often “vicious circles”
Knock-on or domino effects within or between work phases
Knock-on or domino effects between projects
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5
Today’s Agenda
Overview: Causes of Project Dynamics
The Rework Cycle
Integrating Tools in Project Planning
Simple Model of Project Dynamics, Pt. 1
+
-
Network Diagram for NMM Case (from 2010 Homework #1)
a, Start b, Req
c,DieselSpecs
d, ElecDriveSpecs
e,Layout
f,Electronics
Design
g, Software Specs
h, Software Dev
i,DieselDev
j, ElecDriveDev
k,ChassisDesign
l, BodyDesign
m,InternalFittings
s, Body/Chassis
Prototype
p,Electronics
Delivery
q,ElectronicsSoftware
Integ
n,Diesel
Delivery
o,Integra
tionr,
ChargingAssembly
t,Power-Vehicle
Integ
U, FinalAssembly
v,DynamoLab Test
w,RoadTest
x, CarShowSetup
y, Finish
6
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-
7
The Network View of a Program –
Task Accomplishment
Task Accomplishment – Task X
Work to Do Work DoneWork Being
Accomplished
Productivity Staff
7
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Work to Do Work DoneWork Being
Accomplished
Productivity Staff
Network Diagram for NMM Case
a, Start b, Req
c,DieselSpecs
d, ElecDriveSpecs
e,Layout
f,Electronics
Design
g, Software Specs
h, Software Dev
i,DieselDev
j, ElecDriveDev
k,ChassisDesign
l, BodyDesign
m,InternalFittings
s, Body/Chassis
Prototype
p,Electronics
Delivery
q,ElectronicsSoftware
Integ
n,Diesel
Delivery
o,Integra
tionr,
ChargingAssembly
t,Power-Vehicle
Integ
U, FinalAssembly
v,DynamoLab Test
w,RoadTest
x, CarShowSetup
y, Finish
Two stocks and one flow subsumed within each task of network diagram
8
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Work Backlogs and Flow
1,000 Tasks100 Tasks/Month
500 Tasks50 Tasks/Month
0 Tasks0 Tasks/Month
0 5 10 15 20 25 30 35 40 45 50Time (Month)
Work to Do : Traditional View Tasks
Work Done : Traditional View Tasks
Work Being Accomplished : Traditional View Tasks/Month
Aggregate Model of Network View
9
Initial Work to Do = 1000 tasks Productivity = 1 task/mo/person Staff = 40 people
Work Done Work to Do
Work Being Accomplished
Work to Do Work Done
StaffProductivity
Initial Workto Do
Work BeingAccomplished
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10
OR...
Data Often Tell a More Complex Story
Work to Do Work Done
StaffProductivity
Work BeingAccomplished
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10
PRODUCTIVITY?
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Work to Do WorkDone
Rework
x yWork Being
Accomplished
StaffProductivity Fraction Correct
and Complete
z
ReworkCreation
ReworkExecution
Effort is being spent elsewhere …
Sep 11, 2007 11
(0-1: fraction not to be reworked)
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- Definitions
Productivity --
Work accomplished per hour of effort,
regardless of completeness or correctness
Fraction Correct & Complete --
Fraction of work just accomplished that will
not need rework. “Work Quality”
Later we will revisit the iron triangle to
consider “delivered quality.”
12
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OriginalWork to Do Work Done
UndiscoveredRework
Progressx
Fraction Correctand Complete
Time to Discover Rework
Rework toDo
ReworkDiscovery
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Productivity
EffortApplied
Rework
ProgressRework
Generation
++ -
The Rework Cycle
Delay!
13
Delay in Discovering Rework
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-
Work Done
1,000
750
500
250
0
0 5 10 15 20 25 30 35 40 45 50Time (Month)
Ta
sks
Work Done : Traditional With ReworkWork Done : Traditional View
14
Adding Rework Delays Completion …
No Rework
With Rework
Undiscovered Rework
60
45
30
15
0
0 5 10 15 20 25 30 35 40 45 50Time (Month)
Tasks
Undiscovered Rework : Traditional With Rework
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- So, What Happens on Projects?
Staff
Effort on Initial
Work
TIME
Effort on Rework
15
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Rework creates and extended staffing tail
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17
Simulated Actual
Year
800.
600.
400.
200.
0 0 3 6 9 12 15 18 21
ApproximateOriginal Plan
Disguised results from
actual aerospace
project
… Staffing experiences an extended tail
0 3 6 9 12 15 18 21
800.
600.
400.
200.
0
Work Assignments of Staff to...
Original Work
Rework
Total
© 2001 John Wiley & Sons, Ltd. All rights reserved. Thiscontent is excluded from our Creative Commons license.For more information, see http://ocw.mit.edu/fairuse.
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- … or a second staffing peak
17
20
Program Staff, Simulated vs. Data (Equivalent Staff)
400.
300.
200.
100.
TIME
0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6
Simulated Original Plan Actual
Disguised results from
actual vehicle project
… A second staffing peak
Work Assignments of Staff to...
400.
300.
200.
100.
TIME
0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6
Original Work Rework
Disguised results from
actual vehicle project
Rework
Original Work
© 2001 John Wiley & Sons, Ltd. All rights reserved. Thiscontent is excluded from our Creative Commons license.For more information, see http://ocw.mit.edu/fairuse.
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OriginalWork to Do Work Done
UndiscoveredRework
Progressx
Fraction Correctand Complete
Rework toDo
ReworkDiscovery
Productivity
EffortApplied
Rework
Progress+
+Rework
Generation
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Consequences of Undiscovered Rework
1.Overestimates of Progress
18
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19
Additional Metrics (Used in Model)
Fraction Reported to be Complete =
(Work Done + Undiscovered Rework) / Initial Work to Do
Fraction of Work Really Complete =
(Work Done) / Initial Work to Do
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Progress
1
0.75
0.5
0.25
0
0 5 10 15 20 25 30 35 40 45 50Time (Month)
Fra
ctio
n
Fraction Reported Complete : Traditional With Rework3
Fraction Really Complete : Traditional With Rework3
20
Undiscovered rework generates progress-measuring errors …
Reported
Really
Undiscovered Rework
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Rework Cycle Creates “The Lost-Year”...
Design Progress (Percent Complete)
Simulated 100.
75.
50.
25.
0.
Disguised results from actual aerospace project
Time
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9
The Lost Year
Real Progress
21
Source: Ken Cooper
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and the “90% Syndrome” --- Design Progress (Percent Complete)
Simulated100.
75.
50.
25.
0.
TIME1/85 1/89 1/91 1/93 1/95 1/97 1/99 1/01
Disguised results
from actual
aerospace project
Year 1 Year2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8
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- Survey Question 1
Does your organization measure rework?
1. Yes, we keep data on how much rework is being discovered
2. Yes, we keep data on how much work being done is rework (vs original work)
3. Yes, both 1 and 2
4. No, we do not keep data on rework being discovered
23
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- Survey Question 2
Does your organization recognize rework in executing the project?
1. Yes, by adjusting progress estimates to reflect expected remaining undiscovered rework
2. Yes, by building rework tasks into the project graph
3. Both 1 and 2
4. No, we only react as rework is discovered
24
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-
OriginalWork to Do Work Done
UndiscoveredRework
Progressx
Fraction Correctand Complete
Rework toDo
ReworkDiscovery
Productivity
EffortApplied
Rework
Progress+
+Rework
Generation
-
Consequences of Undiscovered Rework
25
1. Overestimates of Progress
2. Build Errors Into Downstream Work
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- Survey Question 3
How significant is the “Errors on Errors” feedback on typical projects in your organization?
1. Very
2. Modest
3. Weak
4. None
26
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- Units of Work – SD Model
“Tasks” -- ideally, of uniform size and
fungible
In actual applications, might use things like:
Drawings, work packages, lines of code, …
Tons of concrete, feet of steel, feet of wiring, ...
Parts designed
Sometimes %
Can represent “precedence” constraints
27
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- “Quality”
Need to distinguish between:
Instantaneous “work quality” (fraction correct and complete)
Delivered “quality” – remaining “bugs” (undiscovered rework) when product shipped
Product capabilities, “fit and finish” (a part of scope in model)
28
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- Fraction Correct and Complete
Represents unplanned iterations; planned iterations are separate tasks
Sources of errors many fold:
Mistakes from inexperience, fatigue, …
Technical complexity/uncertainty
Work done “correctly” but ultimately needing rework because it builds on Incorrect prior work
Assumptions about technology or customer requirements which prove incorrect
29
+
- Two Types of Iteration
Planned Iteration Caused by needs to “get it
right the first time.”
We know where these iterations occur, but not necessarily how much.
Planned iterations should be facilitated by good design methods, tools, and coordination.
Separate tasks in the rework
cycle
Unplanned Iteration Caused by errors and/or
unforeseen problems.
We generally cannot predict which unplanned iterations will occur.
Unplanned iterations should be minimized using risk management methods.
“Quality” problems in the rework cycle
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31
Qualitative Insights
Undiscovered Rework is one of the most important single factors driving schedule and budget overruns
Most management reporting systems overestimate real progress and discourage reporting of rework
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OriginalWork to Do Work Done
UndiscoveredRework
Progressx
Quality
Time to Discover Rework
Rework toDo
ReworkDiscovery
- +
Productivity
EffortApplied
Rework
ProgressRework
Generation
++ -
Lessons: Recognize the rework cycle and minimize its consequences
Fraction Correct and Complete
Increase
Reduce Be Realistic
Overestimates of Progress
Build Errors Into Downstream Work
32
Delay in Discovering Rework
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33
Dynamics of Project Performance
The “rework cycle”
Fraction correct and complete
Undiscovered rework
Feedback effects on productivity and fraction correct (Next class)
Negative, controlling
Positive, re-enforcing, often “vicious circles”
Knock-on effects between work phases (Next)
Availability and quality of work products
Progress to discover upstream rework
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34
Today’s Agenda
Causes of Project Dynamics
The Rework Cycle
Integrating Tools in Project Planning
Simple Model of Project Dynamics, Pt. 1
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-
35
Fundamental Approaches
Network-based (graph theory) methods CPM, PERT, …. Task is a node or an arc
Matrix-based methods DSM - Tasks are columns and rows Interrelationships are off-diagonal entries
System Dynamics Feedback loops, causal relationships Stocks and flows simulation Tasks that are done or waiting to be done
are stocks – “amount of work” Doing project work causes a “flow”
a b
c d e
x x x x x
x x
x x
x
W OR K
BEING DO NE
P EO P LE PRODUCTIVITY
W ORKTO BEDONE
W ORKDONE
What have we learned thus far?
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-
40
1
2
3
7 5 6
4
8
9
10
11
12
13
14
15 16
17
18
19
23
21
22
20
24
28
25
29
27
26 30
31
32 33
35 38 34
37 36
39
Network View of CityCar Project
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-
Network Diagram for NMM Case (from 2010 Homework #1)
a, Start b, Req
c,DieselSpecs
d, ElecDriveSpecs
e,Layout
f,Electronics
Design
g, Software Specs
h, Software Dev
i,DieselDev
j, ElecDriveDev
k,ChassisDesign
l, BodyDesign
m,InternalFittings
s, Body/Chassis
Prototype
p,Electronics
Delivery
q,ElectronicsSoftware
Integ
n,Diesel
Delivery
o,Integra
tionr,
ChargingAssembly
t,Power-Vehicle
Integ
U, FinalAssembly
v,DynamoLab Test
w,RoadTest
x, CarShowSetup
y, Finish
Note: Diesel, Elec Drive, and Software do not show separate “design” and “build” tasks.
37
+
- Organizing the Tasks by “Metatask”
a, Start b, Req
c,DieselSpecs
d, ElecDriveSpecs
e,Layout
f,Electronics
Designg, Software Specs
h,Software
Dev
i,DieselDev
j, ElecDriveDev
k,ChassisDesign
l, BodyDesign
m,InternalFittings
s, Body/Chassis
Prototype
p,Electronics
Delivery
q,ElectronicsSoftware
Integ
n,Diesel
Delivery
o,Integra
tionr,
ChargingAssembly
t,Power-Vehicle
Integ
U, FinalAssembly
v,DynamoLab Test
w,RoadTest
x, CarShowSetup
y, Finish
Requirements Definition
Electronics & Software Design
Body & Chassis Design
Diesel & Electric Drive Design
Vehicle & Power- train Integration
Final Assembly
Testing & Completion
38
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“Gantt” Chart with Metatasks Shown Note: dates approximate; JML estimates of Diesel & Electric, Software Design/Build Split
2010 2011
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Requirements Definition Requirements
a Start 1/1/10 Design
b Requirements 60 1/1/10 3/25/10 a Build/Test
c Diesel Specs 30 3/25/10 5/6/10 b Coupled
d Elec Drive Specs 30 3/26/10 5/6/10 b
g Software Specs 72 3/26/10 7/5/10 b
Body & Chassise Layout 40 3/26/10 6/1/10 b
k Chassis Design 102 6/2/10 10/21/10 e
l Body Design 90 6/2/10 10/5/10 e
s Body Chassis Prototype 48 10/22/10 12/28/10 k,l
Electronics & Softwaref Electronics Design 90 5/7/10 9/9/10 b,c,d
h Software Dev 150 9/10/10 4/7/11 g,f
p Electronics Delivery 72 9/10/10 12/20/10 g,f
q Electronics Software Int 30 4/8/11 5/19/11 h,p
Diesel & Electric Drivei Diesel Dev 180 5/7/10 1/13/11 c
j Elec Drive Dev 90 5/7/10 9/9/10 d
n Diesel Delivery & Check 12 1/14/11 1/31/11 i
Vehicle & Power Train Into Integration 60 2/1/11 4/25/11 j,n
r Charging Assembly 12 4/26/11 5/11/11 j,o
t Power Vehicle Int 60 5/20/11 8/11/11 q,r,s
Final Assemblym Internal Fittings 48 10/22/10 12/28/10 k,l
u Final Assembly 30 8/12/11 9/22/11 m,t
Testing & Completionv Dynamo Lab Test 30 9/23/11 11/3/11 u
w Road Test 72 11/4/11 2/13/12 v
x Car Show Setup 45 11/4/11 1/5/12 v
y Finish 2/13/12
39
+
-
What Messages Come From DSM and SD regarding the network/Gantt plan?
DSM ?
SD ?
How/when is rework discovered?
40
+
-
DSM Identifies Coupled Tasks & Areas of Unplanned Iterations (from Homework #2)
a, Start b, Req
c,DieselSpecs
d, ElecDriveSpecs
e,Layout
f,Electronics
Designg, Software Specs
h,Software
Dev
i,DieselDev
j, ElecDriveDev
k,ChassisDesign
l, BodyDesign
m,InternalFittings
s, Body/Chassis
Prototype
p,Electronics
Delivery
q,ElectronicsSoftware
Integ
n,Diesel
Delivery
o,Integra
tionr,
ChargingAssembly
t,Power-Vehicle
Integ
U, FinalAssembly
v,DynamoLab Test
w,RoadTest
x, CarShowSetup
y, Finish
Requirements Definition
Electronics & Software Design
Body & Chassis Design
Diesel & Electric Drive Design
Vehicle & Power- train Integration
Final Assembly
Testing & Completion
Coupled Tasks – Possible planned Iterations (in design) Unplanned Iterations (why not back to design phase?)
41
+
- “Gantt” Chart With Coupled Tasks Shown
2010 2011
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Requirements Definition Requirements
a Start 1/1/10 Design
b Requirements 60 1/1/10 3/25/10 a Build/Test
c Diesel Specs 30 3/25/10 5/6/10 b Coupled
d Elec Drive Specs 30 3/26/10 5/6/10 b
g Software Specs 72 3/26/10 7/5/10 b
Body & Chassise Layout 40 3/26/10 6/1/10 b
k Chassis Design 102 6/2/10 10/21/10 e
l Body Design 90 6/2/10 10/5/10 e
s Body Chassis Prototype 48 10/22/10 12/28/10 k,l
Electronics & Softwaref Electronics Design 90 5/7/10 9/9/10 b,c,d
h Software Dev 150 9/10/10 4/7/11 g,f
p Electronics Delivery 72 9/10/10 12/20/10 g,f
q Electronics Software Int 30 4/8/11 5/19/11 h,p
Diesel & Electric Drivei Diesel Dev 180 5/7/10 1/13/11 c
j Elec Drive Dev 90 5/7/10 9/9/10 d
n Diesel Delivery & Check 12 1/14/11 1/31/11 i
Vehicle & Power Train Into Integration 60 2/1/11 4/25/11 j,n
r Charging Assembly 12 4/26/11 5/11/11 j,o
t Power Vehicle Int 60 5/20/11 8/11/11 q,r,s
Final Assemblym Internal Fittings 48 10/22/10 12/28/10 k,l
u Final Assembly 30 8/12/11 9/22/11 m,t
Testing & Completionv Dynamo Lab Test 30 9/23/11 11/3/11 u
w Road Test 72 11/4/11 2/13/12 v
x Car Show Setup 45 11/4/11 1/5/12 v
y Finish 2/13/12
Observation/ Question: no coupling between major design phases?
42
+
-
a, Start b, Req
c,DieselSpecs
d, ElecDriveSpecs
e,Layout
f,Electronics
Design
g, Software Specs
h,Software
Dev
i,DieselDev
j, ElecDriveDev
k,ChassisDesign
l, BodyDesign
m,InternalFittings
s, Body/Chassis
Prototype
p,Electronics
Deliveryq,
ElectronicsSoftware
Integ
n,Diesel
Delivery
o,Integra
tionr,
ChargingAssembly
t,Power-Vehicle
Integ
U, FinalAssembly
v,DynamoLab Test
w,RoadTest
x, CarShowSetup
y, Finish
i*,DieselBuild
j*, ElecDriveBuild
f*,Electronics
"Build"
h*,Software"Build"
Network Diagram With “Build” Steps Added and Major Work Phases Highlighted
Requirements Design Build/Test
43
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In an SD Model, Each Phase of Work Could Be Represented by a Rework Cycle
OriginalWork to Do
Work Done
UndiscoveredRework
Original Work Done Correctly
Rework Generation onOriginal Work
Fraction Correctand Complete
Staff
Productivity
Original Work BeingAccomplishmed
Rework BeingAccomplishmed
Rework to Do
ReworkDiscovery
ReworkGeneration on
Rework
Staff on Rework
Staff onOriginal Work
<Initial Work toDo>
44
+
- … Expanded to Three Phases
45
RqmntsOriginal
Work to Do
RqmentsWork Done
RqmentsUndiscovered
Rework
Rqmnts Original Work Done Correctly
Rqmnts ReworkGeneration on Original
Work
RequirementsFraction Correct and
Complete
Requriements Staff
Requirements Productivity
Rqmnts Original WorkBeing Accomplishmed
Rqmnts ReworkBeing
Accomplishmed
RqmntsRework to Do
Rqmnts ReworkDiscovery
Rqmnts ReworkGeneration on
Rework
Rqmnts Staff onRework
Rqmnts Staff onOriginal Work
<Build/Test InitialWork to Do> Design
OriginalWork to Do
Design WorkDone
DesignUndiscovered
Rework
Design Original Work Done Correctly
Design ReworkGeneration on Original
Work
Design FractionCorrect andComplete
Design Staff
Design Productivity
Design Original WorkBeing Accomplishmed
Design ReworkBeing
Accomplishmed
DesignRework to Do
Design ReworkDiscovery
Design ReworkGeneration on
Rework
Design Staff onRework
Design Staff onOriginal Work
<Build/Test InitialWork to Do>
Build/TestOriginal
Work to Do
Build/TestWork Done
Build/TestUndiscovered
Rework
Build/Test Original Work Done Correctly
Build/Test ReworkGeneration on Original
Work
Build/Test FractionCorrect and Complete
Build/Test Staff
Build/Test Productivity
Build/test OriginalWork Being
AccomplishmedBuild/Test Rework
Being Accomplishmed
Build/TestRework to Do
Build/Test ReworkDiscovery
Build/Test ReworkGeneration on Rework
Build/Test Staffon Rework
Build/Test Staff onOriginal Work
<Build/Test InitialWork to Do>
Requirements Design Build/Test
Assumptions: Scope = 100 Tasks Scope = 1000 tasks Scope = 1000 tasks Staff = 4, Staff = 20 Staff = 40 Productivity = 2 tasks/month/person Productivity = 4 tasks/month/person Productivity = 1 tasks/month/person Duration = 12.5 months Duration = 12.5 months Duration = 25 months
+
-
Project Staff
60
45
30
15
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Pe
op
leRequirements Staff : Three P Four Stock No Rework Discrete Start
Design Staff : Three P Four Stock No Rework Discrete Start
"Build/Test Staff" : Three P Four Stock No Rework Discrete Start
Project Staff : Three P Four Stock No Rework Discrete Start
Work Done
2,000
1,500
1,000
500
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Ta
sk
Requirements Work Done : Three P Four Stock No Rework Discrete Start
Design Work Done : Three P Four Stock No Rework Discrete Start
"Build/Test Work Done" : Three P Four Stock No Rework Discrete Start
Simulation of project assuming no rework …
Requirements
Design
Build/Test Requirements
Design
Build/Test Total
46
+
- Sources of Rework -- Categories
1. Classical “Quality” or design mis-execution.
2. Technical complexity/uncertainty; customer uncertainty.
3. Work done “correctly” but ultimately needing rework because it builds on
47
+
- Classical “Quality”
There are two (or more) important sources of these errors – “People” factors such as fatigue, inexperience, skill mismatches,
etc.
“Coupled” tasks that require shared information but which are done independently
Organizational size & complexity?
These types of errors can in theory be discovered by further “design” work, such as doing downstream design work, QA, design reviews, planned iteration, etc.
48
+
-
Technical complexity/uncertainty; customer uncertainty.
Technical: “novelty” of the project
Customer: Same logic might apply to novel/new “uncertain customer requirements”? I.e., where say a software product is being developed and the customer may not know what they want until they see it in practice.]
These types of errors can only be discovered by doing build and test work. Fixing these errors may just require redoing tasks, but may also require new tasks to make the technology work (e.g., and additional controller).
49
+
- “Knock-on” Rework
Work done “correctly” but ultimately needing rework because it builds on Incorrect prior work
Assumptions about technology or customer requirements which prove incorrect.
Exogenous changes in requirements, scope, etc.
These errors could be discovered in design or build/test, depending on the source.
50
+
- How does Design Affect Build?
51
DesignOriginal
Work to Do
Design WorkDone
DesignUndiscovered
Rework
Design Original Work Done Correctly
Design ReworkGeneration on Original
Work
Design FractionCorrect andComplete
Design Staff
Design Productivity
Design Original WorkBeing Accomplishmed
Design ReworkBeing
Accomplishmed
DesignRework to Do
Design ReworkDiscovery
Design ReworkGeneration on
Rework
Design Staff onRework
Design Staff onOriginal Work
<Build/Test InitialWork to Do>
Build/TestOriginal
Work to Do
Build/TestWork Done
Build/TestUndiscovered
Rework
Build/Test Original Work Done Correctly
Build/Test ReworkGeneration on Original
Work
Build/Test FractionCorrect and Complete
Build/Test Staff
Build/Test Productivity
Build/test OriginalWork Being
AccomplishmedBuild/Test Rework
Being Accomplishmed
Build/TestRework to Do
Build/Test ReworkDiscovery
Build/Test ReworkGeneration on Rework
Build/Test Staffon Rework
Build/Test Staff onOriginal Work
<Build/Test InitialWork to Do>
Design FractionReported Complete
Design Fraction of WorkDone Correct and
Complete
Build/Test FractionReported Complete
+
- How is Design Rework Discovered?
52
DesignOriginal
Work to Do
Design WorkDone
DesignUndiscovered
Rework
Design Original Work Done Correctly
Design ReworkGeneration on Original
Work
Design FractionCorrect andComplete
Design Staff
Design Productivity
Design Original WorkBeing Accomplishmed
Design ReworkBeing
Accomplishmed
DesignRework to Do
Design ReworkDiscovery
Design ReworkGeneration on
Rework
Design Staff onRework
Design Staff onOriginal Work
<Build/Test InitialWork to Do>
Build/TestOriginal
Work to Do
Build/TestWork Done
Build/TestUndiscovered
Rework
Build/Test Original Work Done Correctly
Build/Test ReworkGeneration on Original
Work
Build/Test FractionCorrect and Complete
Build/Test Staff
Build/Test Productivity
Build/test OriginalWork Being
AccomplishmedBuild/Test Rework
Being Accomplishmed
Build/TestRework to Do
Build/Test ReworkDiscovery
Build/Test ReworkGeneration on Rework
Build/Test Staffon Rework
Build/Test Staff onOriginal Work
<Build/Test InitialWork to Do>
Design FractionReported Complete
Design Fraction of WorkDone Correct and
Complete
Build/Test FractionReported Complete
+
-
Project Staff
80
60
40
20
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
People
Requirements Staff : Three Phase Four Stock V1
Design Staff : Three Phase Four Stock V1
"Build/Test Staff" : Three Phase Four Stock V1
Project Staff : Three Phase Four Stock V1
Simulation Incorporating Rework and Rework Discovery
Work Done
1,000
750
500
250
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Ta
sk
Requirements Work Done : Three Phase Four Stock V1
Design Work Done : Three Phase Four Stock V1
"Build/Test Work Done" : Three Phase Four Stock V1
Requirements
Design
Build/Test
Requirements Design
Build/Test Total
Notes: (1) Details of simulation do not correspond to NMM Case; (2) so far, we do not represent project control actions and effects, so staff/hours worked are constant.
53
+
-
Design Stocks
1,000
750
500
250
-0.0001
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Ta
sk
Design Original Work to Do : Three Phase Four Stock V1
Design Undiscovered Rework : Three Phase Four Stock V1
Design Rework to Do : Three Phase Four Stock V1
Design Work Done : Three Phase Four Stock V1
Original Work
Undiscovered Rework
Rework
Work Done
54
0
+
-
Design Fraction Complete
2
1.5
1
0.5
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Fra
ctio
n
Design Fraction Original Work Complete : Three Phase Four Stock V1
Design Fraction Reported Complete : Three Phase Four Stock V1
Design Fraction Really Complete : Three Phase Four Stock V1
Fraction Design Rework Discovered
0.8
0.6
0.4
0.2
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Fra
ctio
n
Fraction Design Rework Discovered : Three Phase Four Stock V1
Original Work
Reported
Really
Discovery by design
Discovery by build
55
Progress and Rework Discovery
+
-
Rework Increases Cost and Delays Finish
Cumulative Effort
2,000
1,500
1,000
500
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Pe
rso
n*M
on
ths
Cumulative Reqmnts Effort : Three Phase Four Stock V1
Cumulative Design Effort : Three Phase Four Stock V1
"Cumulative Build/Test Effort" : Three Phase Four Stock V1
Cumulative Effort : Three Phase Four Stock V1
Requirements
Design
Build/Test Total
With Rework
Cumulative Effort
2,000
1,500
1,000
500
0
0 6 12 18 24 30 36 42 48 54 60Time (Month)
Pe
rso
n*M
on
ths
Cumulative Reqmnts Effort : Three P Four Stock No Rework
Cumulative Design Effort : Three P Four Stock No Rework
"Cumulative Build/Test Effort" : Three P Four Stock No Rework
Cumulative Effort : Three P Four Stock No Rework
Without Rework
56
+
-
Revised Network/Gantt to reflect rework discovery (by build, not design)
Insert some Rework Tasks in Design, more in Build/Test
57
2010 2011
Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Design R Rework
Electronics & Software -- Original Build/Test
f Electronics Design 90 5/7/10 9/9/10 b,c,d Coupled
h Software Dev 150 9/10/10 4/7/11 g,f
p Electronics Delivery 72 9/10/10 12/20/10 g,f
q Electronics Software Int 30 4/8/11 5/19/11 h,p
Electronics & Software -- Rework Discovered in Build/Testf Electronics Design 90 5/7/10 9/9/10 b,c,d R R R R Rh Software Dev 150 9/10/10 4/7/11 g,f R R R R R R Rp Electronics Delivery 72 9/10/10 12/20/10 g,f R R R R R Rq Electronics Software Int 30 4/8/11 5/19/11 h,p R R
+
- Management Issues
Planned Iterations (vs dealing with unplanned iterations later) – How many iterations?
When to start build phases – how much overlap with design phases.
Factors to Consider:
Type of project (determines amount of rework discoverable in design, amount of rework, number of tasks which must be repeated for each iteration)
Relative cost of design vs build/test (determines the relative cost of spending more in design)
58
More on these later in term …
+
- Role of Tools
SD:
Evaluate the macro tradeoffs in terms of impact on cost and schedule
Coming up with a good staffing plan
DSM:
Determine where design iterations are needed and how many tasks would need to be repeated per iteration
Network:
Guide operational task planning and resource scheduling
59
+
-
60
Dynamics of Project Performance
The “rework cycle”
Fraction correct and complete
Undiscovered rework
Feedback effects on productivity and fraction correct (Next class)
Negative, controlling
Positive, re-enforcing, often “vicious circles”
Knock-on effects between work phases
Availability and quality of work products
Progress to discover upstream rework
+
-
61
Knock-on Between Phases: A system dynamics model usually represents several phases of work …
S ystem
E n g in eerin g
S o ftw are C o d e
an d T es t
H ard w are
D es ig n
H ard w are B u ild
an d T es t
In teg ra te
an d T es t
S o ftw are
D es ig n
Productivity and Fraction Correct Effects (availability and quality of upstream work)
Rework Discovery Effects
Notes: Suppliers might be a “phase”
+
-
62
Why Represent Separate Phases?
Correspond to gate reviews and deliverables
Different units of work (and therefore data)
Different types of labor
Disproportionate increase in costs of fixing errors as move downstream
Address issues of overlap/concurrency
Opportunity to adjust plans, delay start, between phases
+
-
63
Today’s Agenda
Overview: Causes of Project Dynamics
The Rework Cycle
Integrating Tools in Project Planning
Simple Model of Project Dynamics, Pt. 1
+
-
64
Hard tools force us to be more explicit, and accurately simulate the consequences of our models ...
“Soft” tools --
behavior-over-time graphs
cause-effect diagramming
mental simulation
Tools for describing dynamics
“Hard” tools --
computer models
computer simulation
calibration to data
sensitivity and what-if analyses
Tools for quantifying dynamics
+
- We will use two models …
Simple rework cycle model with project control feedbacks
HW#3 – develop simple model without feedbacks
Feedbacks added in class, given in HW#5
Full rework cycle model with two phases of work
No project control feedback
Model given to you for HW#3 and HW#5
65
+
- Development of “Simple” Project Model 1
Rework cycle model (HW#3)
Three stocks
Variable rework discovery time
“Errors Build Errors” Feedback
Project control & Side Effects (HW#5)
Work Intensity/Schedule Pressure & “Haste Makes Waste”
Staffing & Experience Dilution
Slip Schedule
66
+
- Two Views of the Rework Cycle
Work to Do Work DoneUndiscovered
Rework
Work Accomplishment
Rework Generation
Rework Discovery
Complete Model
Simplified Version
The simplified version assumes that rework tasks require the same effort as original tasks, and that it is not important to distinguish between original work and rework.
Fraction Correct & Complete
OriginalWork to Do Work Done
UndiscoveredRework
Progressx
Rework toDo
ReworkDiscovery
Rework
Progress
67
+
- Simple Rework Cycle Model
68
Steps 1-4 of Homework #3
Work to Do Work DoneUndiscovered
Rework
Work DoneCorrectly
Rework Generation
Rework Discovery
Fraction Correctand Complete
-
Staff
Productivity
Potential Work RateBased on Staffing
Levels
+
+
Project Finished
CumulativeWork Done
Rate of Doing Work
<Rework Generation>
<Work Done Correctly>
Initial Work toDo
CumulativeEffort
ExpendedEffort Expended
Time to DiscoverRework
-
<Project Finished>
+
Work BeingAccomplished
Maximum Work RateBased on Tasks
Available
Minimum Time toFinish a Task
+
+
+
Fraction Completeto Finish
<Initial Work toDo>
+--
+
Normal Staff
+
+
- Rework Discovery Depends on Progress
69
+
- Complete Simple Model 1
70
“Errors on Errors” Feedback
Work to Do Work DoneUndiscovered
Rework
Work DoneCorrectly
Rework Generation
Rework Discovery
Fraction Correctand Complete
Staff
Productivity
Potential Work RateBased on Staff
Project Finished
CumulativeWork Done
Rate of Doing Work
<Rework Generation>
<Work Done Correctly>
Initial Work toDo
Work Believed toBe Done
Fraction ReallyComplete
<Initial Work to Do>
CumulativeEffort
ExpendedEffort Expended
Fraction of Rework Discovered
<Project Finished>
Work BeingAccomplished
Maximum Work RateBased on Tasks
Available
Minimum Time toFinish a Task
Delay inDiscovering Rework
Fraction ReportedComplete
Fraction Completeto Finish
<Initial Work toDo>
Normal Staff
Effect of UndiscoveredRework on Fraction
Correct
Fraction of WorkBelieved Done Correct
and Complete
Normal FractionCorrect and Complete
Maximum Effect ofUndiscovered Rework on
Fraction Correct
Sensitivity of FractionCorrect to Undiscovered
Rework
<Work Done>
This reflects the average delay in
discovering discoverable rework,
such as from QA activities or
downstream work.
This reflects the fraction of
undiscovered rework that is
discoverable at any point in the project
based on the activities tak ing place.
+
-
Effect of Undiscovered Rework on Fraction Correct:
71
Note: The effect of undiscovered rework on fraction correct is assumed to be
proportional -- an error in past work creates an error in current work. Given that in this
simple model fraction correct represents several effects of work errors, this strong
relationship may be reasonable.
Average Work Quality
Graph Lookup - Table for Effect of Prior Work Quality on Quality
1
0
0 1
Effect of Undiscovered Rework on Fraction Correct
Fraction of Work Believed Done Correct and Complete
+
-
Work Flows & Staffing in “Simple” Two Phase Model
72
Design Startup
Project Staff
Design FractionReported Complete
Build/TestStartup
Build/Test Delay inDiscovering Rework
Build/Test FractionReported Complete
Normal DesignFraction Correctand Complete
Build/Test Effect of DesignUndiscovered Rework On
Fraction Correct
Design Fraction of WorkDone Correct and
Complete
Design WorkBelieved to Be Done
Sensitivity of Build/TestFraction Correct to Design
Undiscovered Rework
Normal Build/TestFraction Correct and
Complete
Build/Test WorkBelieved to Be Done
Start DesignRampup
End DesignRampup
Fraction DesignComplete to Start Build
Rampup
Duration of BuildRampup
<Fraction Build/TestRework Discovered>
DesignOriginal
Work to Do
Design WorkDone
DesignUndiscovered
Rework
Design OriginalWork Done Correctly
Design ReworkGeneration on Original
Work
Design FractionCorrect andComplete
Design Staff
<DesignProductivity>
DesignPlanned Staff
Design MinimumTime to Finish a Task
Design Fraction ofEffort to Rework
Design Original WorkBeing Accomplishmed
Design ReworkBeing
Accomplishmed
Design Maximum WorkRate Based on OriginalWork Tasks Available
DesignRework to Do
Design ReworkDiscovery
Design ReworkGeneration on
Rework
Design Staff onRework
DesignProductivity on
Rework
Design Relative EffortRequired for Rework
Design Staff onOriginal Work
Design ReworkDone Correctly
DesignIndicated Staff
Design Maximum WorkRate Based on Rework
Tasks Available
Design Priority toOriginal Work
Build/TestOriginal
Work to Do
Build/TestWork Done
Build/TestUndiscovered
Rework
Build/Test OriginalWork Done Correctly
Build/Test ReworkGeneration on Original
Work
Build/Test FractionCorrect and Complete
Build/Test Staff
<Build/TestProductivity>
Project FinishedSwitch
Build/TestPlanned Staff
Build/Test MinimumTime to Finish a Task
Build/Test Fractionof Effort to Rework
Build/Test OriginalWork Being
Accomplishmed
Build/Test ReworkBeing Accomplishmed
Build/Test Maximum WorkRate Based on OriginalWork Tasks Available
Build/TestRework to Do
Build/Test ReworkDiscovery
Build/Test ReworkGeneration on Rework
Staff on Rework
Build/TestProductivity on
Rework
Build/Test RelativeEffort Required for
ReworkBuild/Test Staff on
Original Work
Build/Test ReworkDone Correctly
<Initial Build/TestWork to Do>
Build/TestIndicated Staff
Build/Test Maximum WorkRate Based on Rework
Tasks Available
Build/Test Priorityto Original Work
<Initial Build/TestWork to Do>
<Design ReworkDiscovered By
Design>
<Design ReworkDiscovered By Build>
<Design RemainingRework Discovered by
Build>
<Initial Build/TestWork to Do>
Build/Test Effect of BuildUndiscovered Rework on
Fraction Correct
Build/Test Fraction of WorkBelieved Done Correct and
Complete
Sensitivity of Build/TestFraction Correct to BuildUndiscovered Rework
<Time>
Maximum Effect ofUndiscovered Rework on
Fraction Correct
Design InitialWork to Do
<Design InitialWork to Do>
Design Effect ofUndiscovered Rework on
Fraction Correct
Sensitivity of DesignFraction Correct to Design
Undiscovered Rework
<Maximum Effect ofUndiscovered Rework on
Fraction Correct>
<Design Effect of BuildWork on Rework
Discovery>
Maximum Sensitivity ofBuild/Test FCC to Design
Undiscovered Rework
Maximum Sensitivity ofBuild/Test Fraction Correct toBuild Undiscovered Rework
<Effect of Build Progresson Build/Test Rework
Discovery>
Maximum Sensitivity ofDesign Fraction Correct to
Design Undiscovered Rework <Fraction ReworkBeing Discovered>
<Design Delay inDiscovering Rework>
Design StaffTotal
<Staff OnReview>
<DesignRework to Do>
<Build/TestRework to Do>
Switch to IncludeRework
<Switch toInclude Rework>
Time to StartBuild Ramp Up
<Time>
<TIME STEP>
Design Build/Test
Four Stock Rework Cycle
+
-
73
Design Phase of Work (Build/Test Similar)
Design Startup
Project Staff
Design FractionReported Complete
Normal DesignFraction Correctand Complete
Design Fraction of WorkDone Correct and
Complete
Design WorkBelieved to Be Done
Start DesignRampup
End DesignRampup
Fraction DesignComplete to Start Build
Rampup
DesignOriginal
Work to Do
Design WorkDone
DesignUndiscovered
Rework
Design OriginalWork Done Correctly
Design ReworkGeneration on Original
Work
Design FractionCorrect andComplete
Design Staff
<DesignProductivity>
DesignPlanned Staff
Design MinimumTime to Finish a Task
Design Fraction ofEffort to Rework
Design Original WorkBeing Accomplishmed
Design ReworkBeing
Accomplishmed
Design Maximum WorkRate Based on OriginalWork Tasks Available
DesignRework to Do
Design ReworkDiscovery
Design ReworkGeneration on
Rework
Design Staff onRework
DesignProductivity on
Rework
Design Relative EffortRequired for Rework
Design Staff onOriginal Work
Design ReworkDone Correctly
DesignIndicated Staff
Design Maximum WorkRate Based on Rework
Tasks Available
Design Priority toOriginal Work
<Design ReworkDiscovered By
Design>
<Design ReworkDiscovered By Build>
<Design RemainingRework Discovered by
Build>
<Time>
Design InitialWork to Do
<Design InitialWork to Do>
Design Effect ofUndiscovered Rework on
Fraction Correct
Sensitivity of DesignFraction Correct to Design
Undiscovered Rework
<Maximum Effect ofUndiscovered Rework on
Fraction Correct>
Maximum Sensitivity ofDesign Fraction Correct to
Design Undiscovered Rework <Fraction ReworkBeing Discovered>
<Design Delay inDiscovering Rework>
Design StaffTotal
<Staff OnReview>
<DesignRework to Do>
Switch to IncludeRework
Design Staff Allocation
of Staff Based on Backlogs, etc.
Rework Discovery
“Errors Create Errors” Feedback
+
- Phase Interconnections
74
Design Startup
Project Staff
Design FractionReported Complete
Build/TestStartup
Build/Test Delay inDiscovering Rework
Build/Test FractionReported Complete
Normal DesignFraction Correctand Complete
Build/Test Effect of DesignUndiscovered Rework On
Fraction Correct
Design Fraction of WorkDone Correct and
Complete
Design WorkBelieved to Be Done
Sensitivity of Build/TestFraction Correct to Design
Undiscovered Rework
Normal Build/TestFraction Correct and
Complete
Build/Test WorkBelieved to Be Done
Start DesignRampup
End DesignRampup
Fraction DesignComplete to Start Build
Rampup
Duration of BuildRampup
<Fraction Build/TestRework Discovered>
DesignOriginal
Work to Do
Design WorkDone
DesignUndiscovered
Rework
Design OriginalWork Done Correctly
Design ReworkGeneration on Original
Work
Design FractionCorrect andComplete
Design Staff
<DesignProductivity>
DesignPlanned Staff
Design MinimumTime to Finish a Task
Design Fraction ofEffort to Rework
Design Original WorkBeing Accomplishmed
Design ReworkBeing
Accomplishmed
Design Maximum WorkRate Based on OriginalWork Tasks Available
DesignRework to Do
Design ReworkDiscovery
Design ReworkGeneration on
Rework
Design Staff onRework
DesignProductivity on
Rework
Design Relative EffortRequired for Rework
Design Staff onOriginal Work
Design ReworkDone Correctly
DesignIndicated Staff
Design Maximum WorkRate Based on Rework
Tasks Available
Design Priority toOriginal Work
Build/TestOriginal
Work to Do
Build/TestWork Done
Build/TestUndiscovered
Rework
Build/Test OriginalWork Done Correctly
Build/Test ReworkGeneration on Original
Work
Build/Test FractionCorrect and Complete
Build/Test Staff
<Build/TestProductivity>
Project FinishedSwitch
Build/TestPlanned Staff
Build/Test MinimumTime to Finish a Task
Build/Test Fractionof Effort to Rework
Build/Test OriginalWork Being
Accomplishmed
Build/Test ReworkBeing Accomplishmed
Build/Test Maximum WorkRate Based on OriginalWork Tasks Available
Build/TestRework to Do
Build/Test ReworkDiscovery
Build/Test ReworkGeneration on Rework
Staff on Rework
Build/TestProductivity on
Rework
Build/Test RelativeEffort Required for
ReworkBuild/Test Staff on
Original Work
Build/Test ReworkDone Correctly
<Initial Build/TestWork to Do>
Build/TestIndicated Staff
Build/Test Maximum WorkRate Based on Rework
Tasks Available
Build/Test Priorityto Original Work
<Initial Build/TestWork to Do>
<Design ReworkDiscovered By
Design>
<Design ReworkDiscovered By Build>
<Design RemainingRework Discovered by
Build>
<Initial Build/TestWork to Do>
Build/Test Effect of BuildUndiscovered Rework on
Fraction Correct
Build/Test Fraction of WorkBelieved Done Correct and
Complete
Sensitivity of Build/TestFraction Correct to BuildUndiscovered Rework
<Time>
Maximum Effect ofUndiscovered Rework on
Fraction Correct
Design InitialWork to Do
<Design InitialWork to Do>
Design Effect ofUndiscovered Rework on
Fraction Correct
Sensitivity of DesignFraction Correct to Design
Undiscovered Rework
<Maximum Effect ofUndiscovered Rework on
Fraction Correct>
<Design Effect of BuildWork on Rework
Discovery>
Maximum Sensitivity ofBuild/Test FCC to Design
Undiscovered Rework
Maximum Sensitivity ofBuild/Test Fraction Correct toBuild Undiscovered Rework
<Effect of Build Progresson Build/Test Rework
Discovery>
Maximum Sensitivity ofDesign Fraction Correct to
Design Undiscovered Rework <Fraction ReworkBeing Discovered>
<Design Delay inDiscovering Rework>
Design StaffTotal
<Staff OnReview>
<DesignRework to Do>
<Build/TestRework to Do>
Switch to IncludeRework
<Switch toInclude Rework>
Time to StartBuild Ramp Up
<Time>
<TIME STEP>
Design Build/Test
Build/Test Progress On Design Rework Discovery
Design “Errors” (Rework) on Build/Test Fraction Correct
Design Rework on Build/Test Productivity
MIT OpenCourseWarehttp://ocw.mit.edu
ESD.36 System Project ManagementFall 2012
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