Intentionally
Vague
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Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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How far do you
live from an
airport?
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I live
!"
minutes from one
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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If I'm in a car
And the weather is good
And it's not rush hour
And I don't blow a tire
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Failing any of these
makes my trip
longer
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimation
and
Trust
Noel Rappin, Table XI
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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I am an
idiosyncratic
crank
about estimates
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Are software developers
uniquely
bad at estimates?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Ever done a
home remodel?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Big Dig
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Initial cost estimate
$5.8 billion
!!!!!!
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Final cost:
$21.93 billion
And counting...
!!!!!!!!!!!
!!!!!!!!!!!
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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It's not just
our
problem
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Why do we
need
to
estimate?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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What about
#noestimates?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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I'll stop
estimating
when my clients stop
asking
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Communication
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating Projects:
Communicates client investment
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating Projects:
Allows us to gauge progress
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating Projects:
Enables us to think about the problem
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating Projects Badly:
Sets unrealistic expectations
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating Projects Badly:
Encourages micromanaging
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating Projects Badly:
Stops us from thinking about the
problem
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating at the
beginning is the
worst
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Like guessing time to the
airport if you don't even
know where the airport is
Or if you even need to fly...
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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How can we estimate
Effectively?
Ethically?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimating projects
vs.
Estimating features
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Nobody
really
cares about estimating
features
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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They only care about when
users can use stuff
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Feature estimates are only
useful to get you to project
estimates
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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A quick sidebar of
agile terms
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Feature
Story
Iteration
Point
Velocity
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Kind of a theory of
ethical
estimates
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimates are
estimates
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimates are
probabilistic
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Chance of rain:
50%
☔
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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We can make bad
assumptions
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Misunderstanding the
problem
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Scope Creep
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Unknown
complexity
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Rework
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Political issues
Optimism
Pressure
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Can we do
better?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Focus on what we're
good at
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Avoid false
precision
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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What goes into the amount
of calendar time a
feature takes?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Complexity of the task
Skill of the developer
Time on task
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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We are bad at estimating
time on task
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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But it tends to be
consistent
over time
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Skill of the developer
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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We're also not that great
at estimating this
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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And it's
toxic
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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But it tends to be
consistent
over time
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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We are pretty good at
estimating
complexity
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Which is to say
!
⚪
!
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Estimate
complexity
and let
time
sort itself out
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Which is like basing our
airport estimate on:
Distance to airport
Average speed in the past
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Consistency
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Of team size
Of story makeup
Of environment
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Decomposing the problem
into similar size chunks
helps
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Requires Time
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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How do I estimate at the
beginning
of a project?
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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The
worst
way to estimate
(except for all the other ways)
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Fake it
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Don't fake
knowledge
or
precision
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Realize that your
output
is a
range
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Split the tasks
as best you can
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Assign points
1: easy, less than a day
3: has complexity or risk
5: has a lot more complexity or risk
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Don't spend a lot of time
assigning points to a single
task
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Round
up
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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At the beginning
(and only at the begining)
You can range estimate
stories
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Range of points
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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load factor
(5 - 7 hours per point)
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Low point total * low
factor
High point total * high
factor
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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points * factor = hours
hours * rate = estimate
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Present this with humility
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Understand that this will
change
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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You are headed to the
airport together
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Thanks
Image credits
4 http://www.constructionequipmentguide.com/
historical/big-dig/
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap
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Noel Rappin
Table XI
@noelrap
http://www.noelrappin.com/trdd
http://pragprog.com/book/nrtest2
Noel Rappin, Estimates and Trust, Ancient City Ruby 2015. http://www.noelrappin.com http://www.tablexi.com @noelrap