CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value / Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey, All Rights Reserved Slide 1
CSE7315M30August 13, 2006
SMU CSE 7315Planning and Managing a
Software Project
Module 30Managing with Earned Value /
Measurement Issues
Slide # 2August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Objectives of This Module• To discuss how to manage a
project using earned value measures
• To discuss some measurement issues
Slide # 3August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Managing with Earned Value
Slide # 4August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
05
101520253035
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TotalPlanEarned$ Spent
BCWS(Budgeted Cost of Work
Scheduled)• The amount of effort you had
planned to expend (i.e., the amount you budgeted)
• “How much work should have been done”
BCWS
Slide # 5August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
05
101520253035
0 1 2 3 4 5 6 7 8 9 10
TotalPlanEarned$ Spent
BCWP(Budgeted Cost of Work
Performed)• The value produced for the effort
you have actually expended• What you have earned• “How much work was actually done”
BCWP
Slide # 6August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
05
101520253035
0 1 2 3 4 5 6 7 8 9 10
TotalPlanEarned$ Spent
ACWP(Actual Cost of Work Performed)
• The amount of money you have spent so far
• The “actual” cost• “What did your work cost?”
ACWP
Slide # 7August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
What Can We Tell About the Schedule
From These Three Numbers?SV - Schedule Variance
SV = BCWP - BCWS
SPI - Schedule Performance IndexSPI = BCWP / BCWS
Negative means behind schedule
Less than 1 means behind schedule
Slide # 8August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
SPI Indicates Whether You are Ahead of or Behind
Schedule
0.5
0.7
0.9
1.1
1.3
1.5
J F M A M J J A S O N D
SPI Target
Ahead of Schedule
Behind Schedule
Slide # 9August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
What Can We Tell About the Cost
From These Three Numbers?CV - Cost Variance
CV = BCWP - ACWP
CPI - Cost Performance Index CPI = BCWP / ACWP
Negative means over budget
Less than 1 means over budget
Slide # 10August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
CPI Indicates Whether You are Under or Over Budget
0.5
0.7
0.9
1.1
1.3
1.5
J F M A M J J A S O N D
CPI Target
Under Budget
Over Budget
Slide # 11August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Variances on Graph
05
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0 1 2 3 4 5 6 7 8 9 10
TotalPlanEarned$ Spent
Schedule VarianceCost
Variance
Slide # 12August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Three Useful NumbersBAC - Budget at Completion
– The total budget for the project– BCWS at project completion (BCWSBAC)
SCHED - Schedule for the project– The total number of weeks or months
or years planned for the projectEAC - Estimate at Completion
– Your estimate of actual project cost (ACWPEAC)
Slide # 13August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
EAC - Your Estimate of theFinal Cost
• This is your estimate of the final project cost, based on your insight on the project.– Perhaps you know that
performance to date is higher or lower than is likely in the future
This is a judged value
Slide # 14August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Independently Estimated Cost At Completion
IEAC - Independent estimate of the project cost at completion– The projected cost of the project, based on
performance so farIEAC = BAC / CPI
– Note that this may be different from your estimate.
This value is based on facts
Slide # 15August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
How Much Over or Under?
VAC - Variance at CompletionVAC = BAC - IEAC
orVAC = BAC - EAC
Negative means over budget by this much
Slide # 16August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Schedule At CompletionISAC - Independent Schedule at Completion
– The projected schedule of the projectISAC = SCHED / SPI
SVAC - Variance at CompletionSVAC = SCHED - ISAC
Negative means behind schedule by this much
Slide # 17August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Thus You Can Tell ...• How far behind or ahead of schedule
you are• How far over or under budget you are• What your eventual schedule and cost
are likely to be
You also have an early warning of trouble that you can use to try to
fix the underlying problems
Slide # 18August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
A Handy Graph of SPI and CPIIndicates Your Overall Status
Behind Schedulebut Under Budget(shortage of staff )
Ahead of Scheduleand Under Budget
Behind Scheduleand Over Budget
Ahead of Schedulebut Over Budget(staff surplus?)
SPI
CPI
Slide # 19August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Reasons for Being Behind Schedule
• If you are also Under Budget– There is not enough work being done
• Not enough people• People being used for other tasks
• If you are at or Over Budget– There is a productivity problem
• Underestimation of the effort• Excessive “non-value-added” work
Slide # 20August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
You Can Set Control Limits and Thresholds for Earned
Value• Just as you can for many other quantities
• Usually based on history from previous programs– Acceptable variation is established by
the behavior of programs that did not get into trouble
This is typically done by mature organizations with good historical data. At lower levels of
maturity, you lack the data to set useful limits.
Slide # 21August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Control Limits on SPI Chart
0.5
0.7
0.9
1.1
1.3
1.5
J F M A M J J A S O N D
SPI Target
Upper Control Limit
Lower Control Limit
Slide # 22August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
What Are Your Chances of Meeting Your Budget?
• If CPI or SPI is outside of the control limits, it means you are under or over performing to a degree that means corrective action is necessary
• But also look at trends - they can indicate potential problems in the future
Slide # 23August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
What If the Budget Changes?• Sometimes projects adjust budgets
and goals – In light of clear evidence that previous
budgets & goals cannot be met– Or due to changes in goals or
requirements– Or due to changes in commitments– Or due to changes in resources– …
• How does this effect earned value?
Slide # 24August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Responding to Budget Changes
• You can continue to track against the original plan, but show new estimates on the same graphs
• You can “replan” – Re-compute BCWS and other values
affected by the change and compute earned value against the new plan
– This is recommended if the new budget is significantly different
Slide # 25August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
What If You Are Asked to Recommend The Adjusted Budget?
• Suppose, in light of clear evidence that previous budgets & goals cannot be met, you are asked to estimate the likely cost and thus the recommended new budget?
• How do you know if the change is enough?
(next slide)
Slide # 26August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
“To Complete”Performance Index
Let BAC be your original budget and EAC be your estimate of actual
costThen TCPI = (BAC-BCWP) / (EAC-ACWP)(work left to do / money left to spend)• This tells you how you must perform
in order to meet your estimate (EAC)
Slide # 27August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Using TCPI (To CompletePerformance Index)
TCPI = (BAC-BCWP) / (EAC-ACWP)• If TCPI is outside the control limits
(i.e., not very close to 1.0), it indicates that, if you continue to perform as you have in the past, you are unlikely to meet the EAC estimate– So you must change the goal – Or take other corrective action
Slide # 28August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
EAC or IEAC?• You can compute TCPI using either
version of EAC.• IEAC assumes your past
performance on the project is a reliable guide – generally recommended after 15-20% complete
• EAC assumes you have information that is more reliable than past performance
Slide # 29August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
SummaryEarned Value Can ...
… tell you your true status… give you an effective schedule /
budget outlook… help you understand the reasons
why if you are not meeting your plan
If the estimates are developed by the workers, they are more likely to “buy in” to
the results
Slide # 30August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Summary (continued)
• Various indices can be computed to tell you things about your project, such as:– Projected cost or schedule– Performance level required to meet a
specific goal (original budget or revised budget)
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value / Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey, All Rights Reserved Slide 31
CSE7315M30August 13, 2006
Measurement Issues
Slide # 32August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Measurement Issues• Frequency• Synchronization• Updating estimates• Margin• Peak vs. average• Units• Interplay of resources
Slide # 33August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
FrequencyHow Often to Measure
• Too often results in high cost, disruption of process
• Too seldom results in failure to see problems soon enough
• Frequency should depend on degree of risk and cost of measurement
0102030
1/yr 1/month 1/week 1/day 1/hour
Eff ectivenessCost
Slide # 34August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
SynchronizationGetting the True Picture
Delay due to System Load
020406080
100120
8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12
Hour
Slide # 35August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
UpdateProjections and Estimates
0
5
10
15
20
25
30
1 2 3 4 5 6 7 8 9 10
ActualForecast
Slide # 36August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
MarginA Frequently Misunderstood
TermWhat does “leave 50% margin” mean?
Code
Margin66 2/3
50
100
100
Code
Margin
Slide # 37August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Peak vs. Average“Software must be able to handle
100 screens per minute”
Peak? (Worst Case)
Average over Some Interval?
How Often to Measure?
Slide # 38August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
UnitsOften Subject to Misinterpretation
• Memory Size: words, bytes, bits???• Program Execution Time:
– Hours since shipped? {was it delivered?}– Hours since received by customer? {was it installed?}– Hours since installed? {was it used?}– CPU execution time since installed?
• CPU Time: cycles, instructions, MIPS, FLOPS, ?
Beware of innocent misinterpretations
Slide # 39August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Interplay of ResourcesFew Things Happen in
IsolationSometimes, system resources interact with each other, giving misleading
evidence of performance
Memory
Capacity:80 cycles
per micro-second
CPU50 MIPS
I/O Channel20 MIPS
Display40 MIPS
CPU may run at only 20 MIPS because of
memory saturation
Slide # 40August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
Summary of Measurement1) Know WHAT you are measuring - attributes,
etc.2) Know WHY you are measuring - goals, risks,
etc.3) Select wisely
– Complete - something for each part of the process
– Reasonable cost of collection– High information content– Minimal organizational disruption
4) Beware of incorrect interpretations5) Beware of misuse
“Nobody believes statistics anyway.”
Adams, The Dilbert Principle
Slide # 41August 13, 2006
CSE 7315 - SW Project Management / Module 30 - Managing with Earned Value /
Measurement IssuesCopyright © 1995-2006, Dennis J. Frailey,
All Rights ReservedCSE7315M30
END OFMODULE 30