What do poker, Greek oracles, an Italian mathematician from the Middle Ages, and the path of hurricanes have in common? Given the title of this presentation, chances are it has something to do with estimation, and you'll have to attend this session to get the full connection. Kent McDonald explores the challenges and realities of trying to estimate software-related knowledge work-analysis, testing, development, and the entire project effort. A major challenge is that there are no guaranteed ways to arrive at perfectly accurate estimates, which not surprisingly is why they are called estimates. Kent introduces and gives you a chance to practice quick and practical estimating techniques that will work in different situations-guesstimating, break it down and add it up, and planning poker. Kent has found that these "lite" estimation techniques are almost always just as informative as the ones you just spent six weeks formulating.

1.
BT9
Concurrent Session
11/8/2012 3:45 PM
"Estimating in Software Development:
No Silver Bullets Allowed"
Presented by:
Kent McDonald
Knowledge Bridge Partners
Brought to you by:
340 Corporate Way, Suite 300, Orange Park, FL 32073
888‐268‐8770 ∙ 904‐278‐0524 ∙ sqeinfo@sqe.com ∙ www.sqe.com

2. Kent McDonald
Knowledge Bridge Partners
Kent McDonald is an author, speaker, and coach who helps organizations improve the
effectiveness of their projects. Kent’s more than fifteen years of experience include work in
business analysis, strategic planning, project management, and product development in a
variety of industries including financial services, health insurance, performance marketing,
human services, nonprofit, and automotive. The co-author of Stand Back and Deliver:
Accelerating Business Agility, Kent currently delivers business analysis training for B2T Training
and shares his thoughts on raising the level of business analysis at BeyondRequirements.com

3. 11/8/2012
Estimating in Software
Development:
No Silver Bullets Allowed
Kent J. McDonald
@beyondreqs
Disclaimer
1

4. 11/8/2012
A Familiar Situation?
Issues with Estimating
Estimating Techniques
Don’t worry, we’ll get to these…
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Has this ever happened to you?
Ok, great. The Sales
How long will it
VP promised an
take to build the
estimate to the
commission
CEO next Monday.
system?
It better be right.
I just found out
about it this
morning, so I’ll need
to do some analysis .
Issues with Estimating
Initial Uncertainty
False Precision
Accuracy/Effort Tradeoff
Differing Skill Levels
3

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Initial Uncertainty
Cone of Uncertainty
4

7. 11/8/2012
Cone of Uncertainty a Practical Use
Hurricane Sandy – Actual Path
5

8. 11/8/2012
Accuracy/Effort
Tradeoff
Point of Diminishing Returns
6

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False Precision
How precise do you have to be?
How long, and
how much?
Approximately 374
days and
$2,548,931.27.
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Differing
skill levels
People finish tasks at different speeds
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Estimating Techniques
Guestimate
Break it down, add it up
Relative Estimating
Guestimate
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12. 11/8/2012
Aka “Gut Feel” or “Ball Park”
How long, and
how much?
About a year and
$2.5 million.
Comparison to Past Projects
$1,000
$100K
$10M
??
$1M
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13. 11/8/2012
Your turn…
Want to create an online application for Mortgage Insurance
How long to deliver the online
application for Mortgage
Insurance?
A ballpark answer is sufficient.
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Does it address our issues?
Initial Uncertainty
False Precision
Accuracy/Effort Tradeoff
Differing Skill Levels
When to use it
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Break it down
Add it up
Break overall effort into bits
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Assign factor to each small bit
Tasks
Time Factor
(hour/bit)
# of
bits
Total Time
(hours)
Interfaces
GUI - Simple
8
GUI - Medium
16
GUI - Hard
24
System Interface - Simple
12
System Interface - Complex
30
Total Interfaces
Processes
Simple Process
16
Medium Process
32
Complex Process
48
Total Processes
Where do we come up with the
factors?
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17. 11/8/2012
This is where time cards may be
useful…
 Know ahead of time
what you want to track
 Build up information
over time
 Often requires
excruciating detail in
time collection.
Identify How Many Bits
Tasks
Time Factor
(hour/bit)
# of
bits
GUI - Simple
8
3
GUI - Medium
16
2
GUI - Hard
24
1
System Interface - Simple
12
Total Time
(hours)
3
Interfaces
System Interface - Complex
30
Total Interfaces
2
11
Processes
Simple Process
16
5
Medium Process
32
4
Complex Process
48
3
Total Processes
12
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Do the math to get an estimate
Tasks
Time Factor
(hour/bit)
# of
bits
Total Time
(hours)
GUI - Simple
8
3
24
GUI - Medium
16
2
32
GUI - Hard
24
1
24
System Interface - Simple
12
3
36
System Interface - Complex
30
2
60
11
176
Interfaces
Total Interfaces
Processes
Simple Process
16
5
80
Medium Process
32
4
128
3
144
12
352
Complex Process
48
Total Processes
This gives us development hours
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19. 11/8/2012
What about analysis & testing &…
 Percentage of
development hours
 Estimate tasks
separately
 You mean we have to
estimate analysis &
testing?
Data Warehouse Example
Adding a new source to
data warehouse
 Count of sources
 Count of tables/source
 Count of
elements/table
 Considerations of
complexity
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20. 11/8/2012
Data Warehouse Example
1. Gather all the info
2. Plug it into a
spreadsheet
3. Look at the resulting
(realistic but “too
high”) number
4. Revise…
Your turn…
Want to create an online application for Mortgage Insurance
How long to deliver the online
application for Mortgage
Insurance?
Identify how you would break
this down to estimate
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Of Course there’s always
Function Points…
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Or, you could always add up tasks
Does it address our issues?
Initial Uncertainty
False Precision
Accuracy/Effort Tradeoff
Differing Skill Levels
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When to use it
Another Look - Decomposition
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24. 11/8/2012
Calibrated Estimates in Ranges
Manage
Tracks
1 – 2 Days
Moderate
Content
3 – 5 Days
Manage
Deadlines
1 – 2 Days
Build
Program
4 – 6 Days
Manage
Venue
.5 – 1 Days
9.5 – 16 Days
@ $100/hour & 8 hours/day
$7,600 – $12,800
Note, Entire team calibrated and
involved in determining these estimates.
For More information
How to Measure Anything:
Finding the Value of
Intangibles in Business
by
Douglas W. Hubbard
HowToMeasureAnything.com
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25. 11/8/2012
Where it Helps
Initial Uncertainty
False Precision
Accuracy/Effort Tradeoff
Differing Skill Levels
Relative Estimating
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26. 11/8/2012
Ah ha! Here’s the poker connection!
Discuss (briefly) the item to estimate
As an Event Organizer
I want to know how
audience members vote by
athlete by gender So That
I can determine if men
and women vote differently.
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The Delphi Technique
Everyone selects an estimate
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28. 11/8/2012
Estimating Scales
(Modified) Fibonacci
Sequence:
0, ½, 1, 2, 3, 5, 8, 13, 20,
40, 80, 100
Using a regular deck of
cards:
A, 2, 3, 5, 8, King
Team Member Hands:
1–5
Leonardo Pisano Bigollo aka Fibonacci
Italian Mathematician
Reveal estimates all at once
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29. 11/8/2012
Discuss outliers
Well, we changed the voting
I wasn’t sure we knew how
machines to ask gender a
Andwhy did youthe two
So how about pick during
Yeah, what she said.
to tell an audience
sign in last iteration, so it
king?
aces?
member’s gender.
should be easy
Repeat until convergence
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30. 11/8/2012
Extrapolate based on Velocity
Assumptions:
 2 week iterations
 Overall backlog size: 600 points
 Planning Velocity: 30
 5 Person Team
 Avg Cost/person/wk: $4,000
Estimate: $800,000
Your turn…
Determine relative sizes of these various
features using the scale 1,2,3,4,5
Based on this feature being sized an 1.
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Does it address our issues?
Initial Uncertainty
False Precision
Accuracy/Effort Tradeoff
Differing Skill Levels
29

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When to use it
An Alternative to Planning Poker
1
2
User Story
3
5
8
User Story
User Story
User Story
User Story
User Story
User Story
User Story
User Story
User Story
User Story
User Story
30

33. 11/8/2012
How should we approach estimating
for a project?
Calibrated
Guestimate
Estimates
Phase Based
Break it
down add
it up
Set
expectation
for revisions
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34. 11/8/2012
Agile
Comparison
Calibrated
to past
Estimates
projects
Extrapolate
from
Velocity
Set
expectation
for revisions
If you remember nothing else
Initial
uncertainty
means you will
not be accurate.
Don’t spend
more effort
than it’s
worth.
Don’t imply
more precision
than is
possible.
Incorporate
multiple
perspectives.
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35. 11/8/2012
Questions?
Kent J. McDonald
kent@kentmcdonald.com
www.BeyondRequirements.com
Twitter: @BeyondReqs
Slides available from:
http://www.knowledgebridgepart
ners.com/presentations/software
estimating/
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