Agile Scope Creep and the Golden Ratio –
Balancing Project Flexibility and Controllability
Copyrights (c) 2011-2013 Pragma...
Responsiveness (Flexibility) Vs
Robustness (Controllability)
• In the history of software development, a struggle has
exis...
Responsiveness (Flexibility) Vs
Robustness (Controllability)
• A Robust software is designed with a lot of care and
upfron...
Scope Creep
• Scope creep is a deviation from an initially agreed-
upon set of requirements that the software
development ...
The Limits of Agility (Flexibility)
• Agile software development is now most favored within the
industry. It is considered...
The Limits of Agility (Flexibility)
• The presentation demonstrates that:
– if Tagile is the time required to complete a s...
The Limits of Agility (Flexibility)
• The Scope Creep Rule can be stated as:
– For each unit of work that you complete as ...
What the Scope Creep Rule does not specify
• The Scope Creep Rule:
– Does not specify how you come up with a
measurement o...
Scope Creep in Agile Methodologies
• In Agile methodologies, a partially complete
and manageable enough set of Requirement...
Scope Creep in Agile Methodologies
• Scope Creep in Agile Sprints/Iterations usually
happens because of:
– The identificat...
Quantifying Scope Creep in Agile
Methodologies (Flexibility)
• Let’s call W the amount of work that was selected
at the be...
Quantifying Scope Creep in Agile
Methodologies (Flexibility)
• The ratio dw/W is the relative amount of new
work added per...
Quantifying Scope Creep in Agile
Methodologies (Flexibility)
• Let P be the overall completion rate if no additional
work ...
Quantifying Scope Creep in Agile
Methodologies (Flexibility)
• Another way of understanding why Pa=0 when dw=W:
– Imagine ...
Agile Completion Time with Scope
Creep
• So if you start with W amount of work and
your Scope Creep ratio is dw/W then the...
Upfront planning and freezing of total
work
• With Upfront planning and freezing, the
development team spends a lot of eff...
Scope Creep in Upfront planning and
freezing of total work
• Scope Creep can also happen in Upfront planning
and freezing ...
Scope Creep in Upfront planning and
freezing of total work
• The important distinction between Agile scope
creep and ‘Upfr...
Quantifying Scope Creep in Upfront planning
and freezing of total work (Controllability)
• Let W be an initially planned a...
• So if you start with W+dw planned amount of
work, the time Tupfront it takes to complete the
total work is:
Tupfront =
𝑊...
Comparing Agile Completion Time (Flexibility) to Upfront
planning and freezing Completion Time (Controllability)
• The que...
• Plotting Tagile and Tupfront as functions of dw for W=100 units of work and
P=50 units of work/week gives:
dw=62
Copyrig...
• The positive analytical solution to:
Tagile =
𝑾 𝟐
𝑷(𝑾−𝒅𝒘)
= Tupfront =
𝑾+𝒅𝒘 𝟐
𝑷.𝑾
Is: dw = 0
and dw =
1
1+ 5
2
W The Gol...
Check the Online Illustration
Copyrights (c) 2011-2013 Pragmatic
Cohesion Consulting
24
Illustration is explained in furth...
Copyrights (c) 2011-2013 Pragmatic
Cohesion Consulting
25
Contact didier@pragmaticohesion.com to learn more about
Controll...
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Agile scope creep and the Golden Ratio – Balancing Project Flexibility and Controllability

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This presentation stipulates that there is a defined ratio of Scope Creep above which Agile approaches lose their edge and become less efficient than methodologies that favor significant Upfront planning and freezing of total work to do.

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  • what a wonderful insight of Scope Creep, Thanks for the information.
    This helps a lot for BA's and PM's to better control the Agile projects in developing robust products allowing a controlled magnitude of change and yet making the projects a Great Success.
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  • I have made edits to the presentation to clarify the following points:
    -the scope creep described in the paper applies to an Agile sprint/Iteration rather than an entire Agile project.
    -scope creep in this paper is not necessarily a 'bad thing' for Agile methodologies as long as it remains moderate in comparison to the initial sprint/iteration scope.
    -the Upfront planning approach is now refer to as the 'Upfront planning and freezing' approach

    Special thanks to all viewers and specially those who provided me with very useful feedback!
       Reply 
    Are you sure you want to  Yes  No
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Agile scope creep and the Golden Ratio – Balancing Project Flexibility and Controllability

  1. 1. Agile Scope Creep and the Golden Ratio – Balancing Project Flexibility and Controllability Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 1
  2. 2. Responsiveness (Flexibility) Vs Robustness (Controllability) • In the history of software development, a struggle has existed between building a Responsive Software product and building a Robust Software product [Rosenberg, Stephens, Collins-Cope]. • A Responsive software product is capable of quickly reacting to changes in software requirements while being developed; it is often the prime attribute of adopting agile methodologies. • The potential drawback of high responsiveness is the loss of robustness when reacting quickly also introduces undetected defects in the software. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 2
  3. 3. Responsiveness (Flexibility) Vs Robustness (Controllability) • A Robust software is designed with a lot of care and upfront considerations so that the software overall architecture remains resilient to changing or new requirements. • The potential drawback of high robustness is the loss of agility due to a slower pace of development as more time is usually spent up front putting in place risk mitigating measures such as: requirements gathering and analysis tasks, Requirements traceability matrices, design documents, unit tests, customer acceptance tests, defect tracking software, etc… Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 3
  4. 4. Scope Creep • Scope creep is a deviation from an initially agreed- upon set of requirements that the software development team must implement. • This presentation does not consider scope creep a “bad thing” by default unless it goes above a given threshold that we are going to determine later on. • Responsive software development or Agile development responds better to moderate scope creep since one of Agile’s main attributes is its ability to quickly adapt to new or changing requirements. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 4
  5. 5. The Limits of Agility (Flexibility) • Agile software development is now most favored within the industry. It is considered much more effective than methodologies that promote Robustness via significant upfront planning and freezing of requirements with more analysis and perhaps more design activities upfront. • This presentation stipulates that there is a defined ratio of Scope Creep above which Agile approaches (Flexibility) lose their edge and become less efficient than methodologies that favor significant Upfront planning and freezing of total work to do (Controllability). • This threshold ratio is the famous Golden Ratio! Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 5
  6. 6. The Limits of Agility (Flexibility) • The presentation demonstrates that: – if Tagile is the time required to complete a sprint/iteration initial amount of work with an ongoing addition of work throughout the entire sprint/iteration on top of the starting amount of work – And if Tupfront is the time required to complete an “initially planned and frozen” amount of work plus a portion of work added to the planned one without adding any more work during the effort Tagile < Tupfront if AdditionalWork < 𝑰𝒏𝒊𝒕𝒊𝒂𝒍 𝑾𝒐𝒓𝒌 𝑮𝒐𝒍𝒅𝒆𝒏 𝑹𝒂𝒕𝒊𝒐 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 6
  7. 7. The Limits of Agility (Flexibility) • The Scope Creep Rule can be stated as: – For each unit of work that you complete as part of an ongoing Agile sprint/iteration effort that starts with an initially planned amount of work, do not add more than 62% ( close to 1/GoldenRatio) new work to your current work, otherwise you would be done faster if you had first added that percentage of the initially planned work to the initial amount of work and then if you had frozen the total work until all work was fully completed. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 7
  8. 8. What the Scope Creep Rule does not specify • The Scope Creep Rule: – Does not specify how you come up with a measurement of the size of the initial amount of work. – Does not specify how you determine the nominal rate at which your development team completes a unit of work. • The following papers are a great references on ways of sizing software work : – ”A Complexity Measure based on Requirement Engineering Document” – “Agile in an Imperfect World” Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 8
  9. 9. Scope Creep in Agile Methodologies • In Agile methodologies, a partially complete and manageable enough set of Requirements is selected for implementation during a Sprint or Iteration to quickly produce a set of software functionality that can be presented to the project sponsor to demonstrate progress and elicit feedback. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 9
  10. 10. Scope Creep in Agile Methodologies • Scope Creep in Agile Sprints/Iterations usually happens because of: – The identification of additional Requirements very relevant to the initial set being implemented – Additional implementation work needed because the development team better understands the existing requirements as it works trough them. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 10
  11. 11. Quantifying Scope Creep in Agile Methodologies (Flexibility) • Let’s call W the amount of work that was selected at the beginning of an agile sprint or iteration. • Let’s call dw the additional amount of work discovered during the sprint or iteration that results from: – The identification of additional Requirements very relevant to the initial set being implemented. – And additional implementation work needed because the development team better understands the existing requirements as it works trough them. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 11
  12. 12. Quantifying Scope Creep in Agile Methodologies (Flexibility) • The ratio dw/W is the relative amount of new work added per completed unit of existing work. • If dw=0 then dw/W=0 so there is 0% new work • If dw=W then dw/W= W/W=1 so there is 100% new work Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 12
  13. 13. Quantifying Scope Creep in Agile Methodologies (Flexibility) • Let P be the overall completion rate if no additional work is created during the sprint/iteration • Let Pa = P.(1-dw/W) be the adjusted completion rate when you have dw additional work. • If dw=0 then Pa =P.(1-0/W) = P, as expected. • If dw=1 then Pa =P.(1-W/W) = 0 • Pa = 0 means that if you always end up having the same amount of remaining work to complete as the amount you started with, you are constantly working with no end in sight; it is as though your overall completion rate is 0. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 13
  14. 14. Quantifying Scope Creep in Agile Methodologies (Flexibility) • Another way of understanding why Pa=0 when dw=W: – Imagine that you are running on a treadmill, if the treadmill was not moving then after a step or two you reach the end of the belt and there is nowhere to go past it. When the treadmill is moving at the same pace as you, when you complete a step or two, you can still run the exact same length of belt as the length you just ran. – From your reference point, your are running and covering some distance, but from the reference point of someone standing next to your treadmill you are not moving. – Pa=0 is how your progress appears to an outside observer waiting for you to complete the work ahead of you during a sprint/iteration. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 14
  15. 15. Agile Completion Time with Scope Creep • So if you start with W amount of work and your Scope Creep ratio is dw/W then the time Tagile it takes you to finish the sprint/iteration total work is: Tagile = 𝑊 𝑃𝑎 = 𝑊 𝑃(1− 𝑑𝑤 𝑊 ) = 𝑊2 𝑃(𝑊−𝑑𝑤) Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 15
  16. 16. Upfront planning and freezing of total work • With Upfront planning and freezing, the development team spends a lot of efforts identifying, quantifying and planning the amount of work needed to complete the implementation of a set of Requirements. • It is important to note that if an Agile project strictly enforces Freezing the Requirements selected for each sprint/iteration prior to beginning work, it behaves like the “Upfront planning and freezing” approach over the scope of the Sprint/Iteration development work. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 16
  17. 17. Scope Creep in Upfront planning and freezing of total work • Scope Creep can also happen in Upfront planning and freezing of total work. • In this case, Scope Creep takes the shape of additional work that will come from new requirements that the development team is considering adding to the initially planned set of Requirements prior to beginning any work. • In this case no new requirements are added once planned work begins and until all work is completed. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 17
  18. 18. Scope Creep in Upfront planning and freezing of total work • The important distinction between Agile scope creep and ‘Upfront planning and freezing” scope creep is that the former happens during the iteration/sprint work while the latter happens before starting the development work. • Because of this distinction, both approaches tackle the complexity and risk added by scope creep differently. The following slides will clarify this point. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 18
  19. 19. Quantifying Scope Creep in Upfront planning and freezing of total work (Controllability) • Let W be an initially planned amount of work • Let dw be the additional amount of work added to W by additional requirements • (W+dw)/W is the ratio of additional work to initial work • Let P be the overall completion rate of work in Upfront planning when there are no new additional work. • Let Pu be the adjusted completion rate in Upfront planning when dw work is added to W. • Pu = P.W/(W+dw), Pu decreases as more work is added upfront because of the added complexity of the total work. • If dw=0 then Pu = P.W/(W+0) = P.W/W = P Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 19
  20. 20. • So if you start with W+dw planned amount of work, the time Tupfront it takes to complete the total work is: Tupfront = 𝑊+𝑑𝑤 𝑃𝑢 = 𝑊+𝑑𝑤 𝑃.𝑊 𝑊+𝑑𝑤 = 𝑊+𝑑𝑤 2 𝑃.𝑊 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 20 Quantifying Scope Creep in Upfront planning and freezing of total work (Controllability)
  21. 21. Comparing Agile Completion Time (Flexibility) to Upfront planning and freezing Completion Time (Controllability) • The question is: for a given Scope Creep ratio dw/W, which approach completes the total amount of work W first? • We are comparing:  Tagile = 𝑾 𝟐 𝑷(𝑾−𝒅𝒘) to Tupfront = 𝑾+𝒅𝒘 𝟐 𝑷.𝑾 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 21
  22. 22. • Plotting Tagile and Tupfront as functions of dw for W=100 units of work and P=50 units of work/week gives: dw=62 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 22 Comparing Agile Completion Time (Flexibility) to Upfront planning and freezing Completion Time (Controllability) Flexibility Wins Controllability Wins
  23. 23. • The positive analytical solution to: Tagile = 𝑾 𝟐 𝑷(𝑾−𝒅𝒘) = Tupfront = 𝑾+𝒅𝒘 𝟐 𝑷.𝑾 Is: dw = 0 and dw = 1 1+ 5 2 W The Golden Ratio = 𝟏+ 𝟓 𝟐 = W/dw Tagile < Tupfront if AdditionalWork < 𝑰𝒏𝒊𝒕𝒊𝒂𝒍 𝑾𝒐𝒓𝒌 𝑮𝒐𝒍𝒅𝒆𝒏 𝑹𝒂𝒕𝒊𝒐 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 23 Comparing Agile Completion Time (Flexibility) to Upfront planning and freezing Completion Time (Controllability)
  24. 24. Check the Online Illustration Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 24 Illustration is explained in further details at the above link!
  25. 25. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 25 Contact didier@pragmaticohesion.com to learn more about Controlling your Software Delivery Schedule and Cost. http://pragmaticohesion.com/ Check the Online Illustration

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