Lies, damn lies, estimates

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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.

Published in: Technology, Business

Lies, damn lies, estimates

  1. 1. ©ClaysnowLimited2014 Lies, damn lies and estimates Seb Rose Claysnow Limited www.claysnow.co.uk @sebrose Tuesday, 15 April 14
  2. 2. ©ClaysnowLimited2014 Tuesday, 15 April 14
  3. 3. ©ClaysnowLimited2014 DISRAELI Tuesday, 15 April 14
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  8. 8. ©ClaysnowLimited2014 Tuesday, 15 April 14
  9. 9. ©ClaysnowLimited2014 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 Tuesday, 15 April 14
  10. 10. ©ClaysnowLimited2014 Your company NEEDS that estimate soonnowyesterday (Of course we won’t hold you to it) Tuesday, 15 April 14
  11. 11. ©ClaysnowLimited2014 The project status is still green We’re 90% done We will deliver with zero defects On time, on budget every project It’s working in the test environment Integration takes hardly any time Tuesday, 15 April 14
  12. 12. ©ClaysnowLimited2014 Prediction is very difficult, especially about the future. Niels Bohr, physicist Tuesday, 15 April 14
  13. 13. ©ClaysnowLimited2014 Tuesday, 15 April 14
  14. 14. ©ClaysnowLimited2014 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) Tuesday, 15 April 14
  15. 15. ©ClaysnowLimited2014 6. Introduction to Estimation Techniques 7. Count, Compute, Judge 8. Calibration and Historical Data 9. Individual Expert Judgement 10. Decomposition and Recomposition 11. Estimation by Analogy 12. Proxy-Based Estimates 13. Expert Judgement in Groups 14. Software Estimation Tools 15. Use of Multiple Approaches 16. Flow of Software Estimates on a Well- Estimated Project 17. Standardized Estimation Procedures Part II - Fundamental Estimation Techniques Tuesday, 15 April 14
  16. 16. ©ClaysnowLimited2014 Tuesday, 15 April 14
  17. 17. ©ClaysnowLimited2014 Tuesday, 15 April 14
  18. 18. ©ClaysnowLimited2014 The Cone of Uncertainty in Project Management Tuesday, 15 April 14
  19. 19. ©ClaysnowLimited2014 Tuesday, 15 April 14
  20. 20. ©ClaysnowLimited2014 Overconfidence Tuesday, 15 April 14
  21. 21. ©ClaysnowLimited2014 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 Tuesday, 15 April 14
  22. 22. ©ClaysnowLimited2014 Example: Q. How many people are in this room? You ‘guess’ an interval: Low: 30, High: 100 Tuesday, 15 April 14
  23. 23. ©ClaysnowLimited2014 What was the date of birth of Bram Stoker, author of Dracula? Question 1: Tuesday, 15 April 14
  24. 24. ©ClaysnowLimited2014 What is the population of the Republic of Brazil? Question 2: Tuesday, 15 April 14
  25. 25. ©ClaysnowLimited2014 What is the height, in meters, of the tallest living redwood tree? Question 3: Tuesday, 15 April 14
  26. 26. ©ClaysnowLimited2014 How many standardized (ISO 6346) steel shipping containers exist in the world? Question 4: Tuesday, 15 April 14
  27. 27. ©ClaysnowLimited2014 How many Boeing 747 (all models) have been built at this date? Question 5: Tuesday, 15 April 14
  28. 28. ©ClaysnowLimited2014 What is the total number of human deaths attributed to H5N1 “avian” flu? Question 6: Tuesday, 15 April 14
  29. 29. ©ClaysnowLimited2014 How many Syrian conflict refugees were registered by UNHCR as of 1 Nov 2012? Question 7: Tuesday, 15 April 14
  30. 30. ©ClaysnowLimited2014 What was the total wine production of France in 2009, in hectolitres? Question 8: Tuesday, 15 April 14
  31. 31. ©ClaysnowLimited2014 How many Olympics medals altogether have been won to date by Austrian athletes? Question 9: Tuesday, 15 April 14
  32. 32. ©ClaysnowLimited2014 What is the half-life, in years, of the isotope Plutonium 239? Question 10: Tuesday, 15 April 14
  33. 33. ©ClaysnowLimited2014 1) 1847 2) 199 million 3) 115 meters 4) 20 million 5) 1486 6) 379 7) 286,000 8) 45 million hectolitres 9) 304 10) 24 thousand years Tuesday, 15 April 14
  34. 34. ©ClaysnowLimited2014 How did you do? Tuesday, 15 April 14
  35. 35. ©ClaysnowLimited2014 "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 Tuesday, 15 April 14
  36. 36. ©ClaysnowLimited2014 Why do we estimate? Tuesday, 15 April 14
  37. 37. ©ClaysnowLimited2014 Forecasting Tuesday, 15 April 14
  38. 38. ©ClaysnowLimited2014 Tracking Tuesday, 15 April 14
  39. 39. ©ClaysnowLimited2014 Tuesday, 15 April 14
  40. 40. ©ClaysnowLimited2014 “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 Tuesday, 15 April 14
  41. 41. ©ClaysnowLimited2014 “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 Tuesday, 15 April 14
  42. 42. ©ClaysnowLimited2014 http://leadinganswers.typepad.com/leading_answers/files/original_waterfall_paper_winston_royce.pdf The original “waterfall” paper - Winston Royce, 1970 Tuesday, 15 April 14
  43. 43. ©ClaysnowLimited2014 Tuesday, 15 April 14
  44. 44. ©ClaysnowLimited2014 Tuesday, 15 April 14
  45. 45. ©ClaysnowLimited2014 Tuesday, 15 April 14
  46. 46. ©ClaysnowLimited2014 Tuesday, 15 April 14
  47. 47. ©ClaysnowLimited2014 How long is a piece of string? Tuesday, 15 April 14
  48. 48. ©ClaysnowLimited2014 Tuesday, 15 April 14
  49. 49. ©ClaysnowLimited2014 120 cm 100 cm 70 cm 60 cm 40 cm E. D. C. A. B. Tuesday, 15 April 14
  50. 50. ©ClaysnowLimited2014 ... 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 Tuesday, 15 April 14
  51. 51. ©ClaysnowLimited2014 Tuesday, 15 April 14
  52. 52. ©ClaysnowLimited2014 12 cm 10 cm 7 cm 6 cm 4 cm E. D. C. A. B. Tuesday, 15 April 14
  53. 53. ©ClaysnowLimited2014 Is it small, or just far away? Tuesday, 15 April 14
  54. 54. ©ClaysnowLimited2014 Tuesday, 15 April 14
  55. 55. ©ClaysnowLimited2014 winnipegagilist.blogspot.com Tuesday, 15 April 14
  56. 56. ©ClaysnowLimited2014 “If a project has no risks, don’t do it.” “Waltzing with bears”, DeMarco & Lister, 2003 Tuesday, 15 April 14
  57. 57. 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. Tuesday, 15 April 14
  58. 58. ASSUME YOU'RE IGNORANT Tuesday, 15 April 14
  59. 59. ©ClaysnowLimited2014 “... during an inception, when we are most ignorant about most aspects of the project, the best use we can possibly make of the time available is to attempt to identify and reduce our ignorance” http://dannorth.net/2010/08/30/introducing-deliberate-discovery/ Deliberate discovery Tuesday, 15 April 14
  60. 60. ©ClaysnowLimited2014 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 Tuesday, 15 April 14
  61. 61. ©ClaysnowLimited2014 Dave Snowden, released under CC BY 3.0 Cynefin Tuesday, 15 April 14
  62. 62. ©ClaysnowLimited2014 http://www.tylerjanderson.com/case-study-roi-of-facebook-advertising/ Tuesday, 15 April 14
  63. 63. ©ClaysnowLimited2014 ROI = x 100 (Investment Gain - Investment Cost) (Investment Cost) Tuesday, 15 April 14
  64. 64. ©ClaysnowLimited2014 Impact mapping http://impactmapping.org/about.php Tuesday, 15 April 14
  65. 65. ©ClaysnowLimited2014 Tuesday, 15 April 14
  66. 66. ©ClaysnowLimited2014 Cost of delay http://blackswanfarming.com/cost-of-delay/ ... is a way of communicating the impact of time on value. Tuesday, 15 April 14
  67. 67. ©ClaysnowLimited2014 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 Tuesday, 15 April 14
  68. 68. ©ClaysnowLimited2014 #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 unknowns Estimating sprint velocity is waste Iterate, don’t estimate Shift focus to “small” Agile team, same old contract Quality is variable, not fixed Don’t deliver requirements, deliver what the customer wants Tuesday, 15 April 14
  69. 69. ©ClaysnowLimited2014 ... crying “No estimates, no backlogs, no deadlines” ... [is] not very effective nor efficient. http://xprogramming.com/articles/artifacts-are-not-the-problem/ Tuesday, 15 April 14
  70. 70. ©ClaysnowLimited2014 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/ Tuesday, 15 April 14
  71. 71. ©ClaysnowLimited2014 Giving software projects an API ... [is] about “yes, yes, yes”. http://xprogramming.com/articles/artifacts-are-not-the-problem/ Tuesday, 15 April 14
  72. 72. ©ClaysnowLimited2014 All models are wrong, but some are useful George Box, statistician Tuesday, 15 April 14
  73. 73. ©ClaysnowLimited2014 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%2C0 Tuesday, 15 April 14
  74. 74. ©ClaysnowLimited2014 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. Tuesday, 15 April 14
  75. 75. ©ClaysnowLimited2014 “Old fogies know your estimates will be bogus. They know you won’t get them right. They know you won’t hit the deadline with full scope” http://xprogramming.com/articles/artifacts-are-not-the-problem/ Tuesday, 15 April 14
  76. 76. ©ClaysnowLimited2014 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 Tuesday, 15 April 14
  77. 77. ©ClaysnowLimited2014 -JVM Seb Rose, Available 2014 (hopefully) Tuesday, 15 April 14
  78. 78. Seb  Rose Twi$er:     @sebrose Blog:       www.claysnow.co.uk E-­‐mail:     seb@claysnow.co.uk Tuesday, 15 April 14
  79. 79. ©ClaysnowLimited2014 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 Tuesday, 15 April 14

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