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Presented at ACCU 2014 (accu.org) Are estimates an essential part of project planning and delivery or a waste of everybody's time? As is so often the case the answer is neither and both. In this session we discover that there is more than one kind of estimate and examine how they are typically used in an agile context. We look at what some of the great minds have said on the subject, from Steve McConnell to Demarco and Lister. We'll also consider the need for estimates from the viewpoint of the business people who have to decide whether a project proposal should receive budget. Picking up the 'No Estimates' discussion from Twitter, we'll see if there's a case to be made for always refusing to provide estimates or whether there are times that some sorts of estimation is valuable. I may not change your mind, but I intend to widen your perspective.
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© C
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Lies, damn lies and estimates
Seb RoseClaysnow Limited
www.claysnow.co.uk
@sebrose
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DISRAELI
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I’ll be back tomorrow to finish off
You’ll be in by Christmas
That will be fixed before we
leave
All our previous customers are
completely satisfied
We don’t make mistakes like other
builders
You won’t notice we’re there
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Your companyNEEDS
that estimatesoonnowyesterday
(Of course we won’t hold you to it)
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The project status is still green
We’re 90% doneWe will deliver
with zero defects
On time, on budget every project
It’s working in the test environment
Integration takes hardly any
time
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Prediction is very difficult,
especially about the future.
Niels Bohr, physicistTuesday, 15 April 14
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The primary purpose of an estimate is not to predict a project’s outcome;
it is to determine whether a project’s targets are realistic enough to allow the project to be controlled to meet them.
Steve McConnell, Software Estimation (2006)
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6. Introduction to Estimation Techniques7. Count, Compute, Judge8. Calibration and Historical Data9. Individual Expert Judgement10. Decomposition and Recomposition11. Estimation by Analogy12. Proxy-Based Estimates13. Expert Judgement in Groups14. Software Estimation Tools15. Use of Multiple Approaches16. Flow of Software Estimates on a Well-
Estimated Project17. Standardized Estimation Procedures
Part II - Fundamental Estimation Techniques
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The Cone of Uncertainty in Project Management
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Overconfidence
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For each of the next 10 quantitative questions, give a lower and an upper bound,
such that you believe with about 90% certainty that the
correct answer lies within the interval given.
This means that you should expect to guess correctly for about 9 questions out of 10.
Laurent Bossavit, www.bossavit.com, @morendil
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Example:
Q. How many people are in this room?
You ‘guess’ an interval:Low: 30, High: 100
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What was the date of birth of Bram Stoker, author of Dracula?
Question 1:
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What is the population of the Republic of Brazil?
Question 2:
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What is the height, in meters, of the tallest living redwood tree?
Question 3:
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How many standardized (ISO 6346) steel shipping containers exist in the world?
Question 4:
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How many Boeing 747 (all models) have been built at this date?
Question 5:
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What is the total number of human deaths attributed to H5N1 “avian” flu?
Question 6:
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How many Syrian conflict refugees were registered by UNHCR as of 1 Nov 2012?
Question 7:
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What was the total wine production of France in 2009, in hectolitres?
Question 8:
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How many Olympics medals altogether have been won to date by Austrian athletes?
Question 9:
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What is the half-life, in years, of the isotope Plutonium 239?
Question 10:
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1) 18472) 199 million3) 115 meters4) 20 million5) 14866) 3797) 286,0008) 45 million hectolitres9) 30410) 24 thousand years
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How did you do?
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"We aren't really bad at estimating.
What we are really bad at is enumerating all the assumptions that lie behind our estimates."
-Paul Rook
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Forecasting
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Tracking
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“A boundary object is a concept in sociology to describe information used in different ways by different communities. They are plastic, interpreted differently across communities but with enough immutable content to maintain integrity”
--Wikipedia
Estimates are Boundary Objects
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“They are weakly structured in common use, and become strongly structured in individual-site use. They may be abstract or concrete.
They have different meanings in different social worlds but their structure is common enough to more than one world to make them recognizable means of translation.
The creation and management of boundary objects is key in developing and maintaining coherence across intersecting social worlds.”
-- Leigh & Griesemer
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http://leadinganswers.typepad.com/leading_answers/files/original_waterfall_paper_winston_royce.pdf
The original “waterfall” paper - Winston Royce, 1970
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How long is a piece of string?
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120 cm100 cm70 cm60 cm40 cm
E.D.C.A.B.
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... these studies which have for a few years now given rise to the claim that "research shows that people are better at relative than absolute estimation" do not in fact seem to square with that claim.
This doesn't entail that relative estimation doesn't work - only that it is not proven.
http://guide.agilealliance.org/guide/relative.html
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12 cm10 cm7 cm6 cm4 cm
E.D.C.A.B.
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Is it small, or just far away?
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winnipegagilist.blogspot.comTuesday, 15 April 14
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“If a project has no risks, don’t do it.”
“Waltzing with bears”, DeMarco & Lister, 2003
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There are known knowns; there are things we know that we know.
There are known unknowns; that is to say there are things that, we now know we don't know.
But there are also unknown unknowns – there are things we do not know we
don't know.
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ASSUME YOU'RE
IGNORANTTuesday, 15 April 14
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“... during an inception, when we aremost ignorant
about most aspects of the project,the best use
we can possibly make of the time available is to attempt to
identify and reduceour ignorance”
http://dannorth.net/2010/08/30/introducing-deliberate-discovery/
Deliberate discovery
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1. Just about everyone in the world has done this.
2. Lots of people have done this, including several people in the company.
3. Someone in our company has done this.4. Someone in the world did this, but not in
our organisation (and probably at a competitor).
5. Nobody has ever done this before.
http://lizkeogh.com/2013/07/21/estimating-complexity/
Estimating Complexity
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Dave Snowden, released under CC BY 3.0
Cynefin
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http://www.tylerjanderson.com/case-study-roi-of-facebook-advertising/Tuesday, 15 April 14
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ROI = x 100(Investment Gain - Investment Cost)
(Investment Cost)
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Impact mapping
http://impactmapping.org/about.php
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Cost of delay
http://blackswanfarming.com/cost-of-delay/
... is a way of communicating the impact of time on value.
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Cost of delay
http://blackswanfarming.com/cost-of-delay/
1.Better Decision-making – by making the economic trade-offs visible
2.Better Prioritisation – by using CD3 (Cost of Delay Divided by Duration) we deliver more total value
3.By changing the focus – from efficiency and cost (which encourages the wrong behaviours), to speed and value
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#NoEstimates
http://neilkillick.com/2013/02/08/noestimates-part-2-contract-negotiation-and-the-old-banger/
http://neilkillick.com/2013/01/31/noestimates-part-1-doing-scrum-without-estimates/
Remove the unknownsEstimating sprint velocity is wasteIterate, don’t estimateShift focus to “small”
Agile team, same old contractQuality is variable, not fixedDon’t deliver requirements, deliver what the customer wants
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... crying “No estimates,
no backlogs, no deadlines”
... [is] not very effective nor efficient.
http://xprogramming.com/articles/artifacts-are-not-the-problem/
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Done conventionally, software projects offer almost no information, and almost no control, to those who are given the responsibility to manage them.
... the people in charge of spending money to get software really do need control and information.
Saying “no” doesn’t help them.
http://xprogramming.com/articles/artifacts-are-not-the-problem/
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Giving software projects an API
... [is] about “yes, yes, yes”.
http://xprogramming.com/articles/artifacts-are-not-the-problem/
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All models are wrong,
but some are useful
George Box, statisticianTuesday, 15 April 14
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Dear Customer
... when we start an IT project, we don’t know how much time and effort it will take to complete.
Consequently, we don’t know how much it will cost.
http://www.agileconnection.com/article/dear-customer-truth-about-it-projects?page=0%2C0Tuesday, 15 April 14
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Dear Customer
http://www.agileconnection.com/article/dear-customer-truth-about-it-projects?page=0%2C0
... the more details you try to give us beforehand, the more likely your desires are to change.
Each time you give us more detail, you are offering more hostages to fortune.
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“Old fogies knowyour estimates will be bogus.
They know youwon’t
get them right.
They know youwon’t
hit the deadline with full scope”
http://xprogramming.com/articles/artifacts-are-not-the-problem/
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Challenge the use of estimates - understand its value
Estimates are not commitments - make this crystal clear
Is it small or just far away - ignorance is the major constraint
Take aways
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-JVM
Seb Rose,
Availa
ble 20
14
(hopef
ully)
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Estimates produced before a project starts are lies about how much something will cost, usually tailored depending on whether the source of the estimate wants the project to go ahead or not.
Estimates produced once a project has started are lies that compensate for the inaccuracies of earlier estimates.
Both contribute towards an illusion of control that is no more real in software than it is in civil engineering.
http://accu.org/index.php/journals/1836
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