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Iterative ProjectManagement
Chapter 7.2 – Evolution and Phase Planning
Modified considerably by your Instructor
2Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Overview: Iterations Across The Lifecycle
• Inception– Executable release optional
– May only be one iteration
• Elaboration– Demonstrate critical use cases
– Result in executable architecture
• Construction– Result in usable software
– Typically two or more iterations
• Transition– Releases based on feedback and fixes
Early iterations address:
• High risks
• Stability
• Understanding
Late iterations address:
•Functionality
•Performance
•Robustness
3Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Planning an Evolution:Iteration Patterns – To show different Strategies…
• Incremental Development• Evolutionary Development• Incremental Delivery• Extreme Programming / No Elaboration• Immediate Construction / Virtual Phases
4Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
An Incremental Development Strategy (1 of 2)
• This is the ‘ideal’ iteration pattern offering all the benefits of ‘rapid application development’ (RAD) without the risks. (Slide next page)
• “The incremental strategy determines user needs and defines the system requirements, then performs rest of development in a sequence of builds.
• The first build incorporates parts of the planned capabilities, the next build adds more capabilities, and so on until the system is complete.” [Software Development and Documentation, MIL-STD-498, U.S. Department of Defense, 12/1994]
• The following iterations are characteristic: • a short Inception iteration to establish scope, vision; define business case • a single Elaboration iteration; requirements defined, architecture established • several Construction iterations; use cases realized, architecture fleshed-out • several Transition iterations, migrate product into the user community
•
5Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Incremental Development - Strategy
This strategy is appropriate when: • Problem domain is familiar.• Architecture is already proven / familiar • Risks well understood and under control• Team is experienced. • A RAD approach….
Time
Resources
Inception Elaboration Construction Transition
Conceptual Prototype
ArchitecturalBaseline
Release Delivery
6Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Evolutionary Development – Strategy (1 of 2)
• This is the pattern that most team’s first iterative and incremental evolution conforms to. (Slide next page)
• "The evolutionary strategy differs from the incremental in acknowledging user needs are not fully understood, and requirements cannot be defined up front, – Requirements are refined in each successive build." [MIL-STD-498]
• The following iterations are characteristic: • Short Inception iteration - establish scope, vision; define business case • Several Elaboration iterations; requirements refined at each iteration and
the architecture evolved• One or two Construction iterations; use cases realized, architecture is
expanded upon; the application given a final polish • Several Transition iterations to migrate product into user community
•
7Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Evolutionary Development
This strategy is appropriate when: • Problem domain - new or unfamiliar.• Architecture - new or unfamiliar all high risk• Iterative development - new or unfamiliar factors…• Team - inexperienced. • (note: number of iterations only for illustrative purposes)
Time
Resources
Inception Elaboration Const’n Transition
Conceptual Prototype
ArchitecturalBaseline
Release Delivery
8Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
An Incremental Delivery Strategy…(1 of 2)
• Pattern where multiple deliveries provided to customer is quite common for Internet site development where new content releases are expected monthly
• May be required for tight time-to-market pressures, where delivery of certain key features early can yield significant business benefits. [Tom Gilb, Principles of Software Engineering Management, Wokingham, Addison-Wesley, 1988].
• In terms of the phase-iteration approach, the transition phase begins early on and has the most iterations.
Strategy requires a very stable architecture, which is hard to achieve in an initial development cycle, for an "unprecedented" system.
• The following iterations are characteristic: • Short Inception iteration: establish scope, vision: define business case • Single Elaboration iteration - a stable architecture is baselined • Single Construction iteration: use cases realized; architecture fleshed-out • Several Transition iterations each of which delivers a new release of the
product (with increased functionality) into the user community
9Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Incremental Delivery Strategy (2 of 2)
This strategy is appropriate when: • Small increments have high value to the customer.• The architecture is already proven and familiar• The requirements are stable and low risk• The team is experienced in the architecture and the
domain
Time
Resources
Inception Elaboration Const’n Transition
Conceptual Prototype
ArchitecturalBaseline
Delivery DeliveryDelivery Delivery Delivery Delivery
10Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Immediate Construction / Virtual Phases (1` of 2)
• In some cases, anchor point milestones can be merged. • A project deciding to use a mature and appropriately scalable
4th generation language (4GL) or product line framework will have already determined its choice of life cycle architecture by its LCO milestone enabling the LCO and LCA milestones to be merged.
• As Barry Boehm observed, in his paper Spiral Development: Experience, Principles and Refinements (CMU/SEI-2000-SR-008),
• Merging of the milestones is often compounded by the fact that another project (typically a feasibility project or the previous release) has already done the work for you.
• Leads to pattern appearing like no Inception or Elaboration • In this case the phases have been suppressed but the
milestones are still there, with the reviews being undertaken before the set of construction iterations can commence.
11Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Immediate Construction / Virtual Phases (2 of 2)
This strategy is appropriate when: • Architecture already proven and familiar• Requirements are known and of low technical risk• Team is experienced in the architecture and the domain• Project is collaborative and informal
Time
Resources
Construction Transition
LCO and LCAPassed
FirstRelease
Delivery
12Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
No Elaboration Strategy
• This is another variant where milestones have been merged providing impression of no Elaboration Phase.
• Enter most ‘Extreme Programming’ and SCRUM projects Architecture is a given at the start of the set of
development iterations. • Architecture can be adjusted by refactoring during
Construction but this is typical of most iterative and incremental projects post LCA.
• Some Extreme Programming authors, most noticeably Martin Fowler, would allow technical concerns to affect the allocation of work to the initial development iterations creating an informal Elaboration Phase.
13Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Agile’s Terminology – via Kent Beck
• Note In Agile and Iterative Development a Manager’s Guide, the XP Lifecycle phases as defined by Beck are described as:
• Exploration - Purpose: Enough well-estimated story cards for first release, feasibility ensured. – Activities: Prototypes, exploratory proof of technology programming, story card
writing and estimating
• Planning - Purpose: Agree on date and stories for first release. – Activities: Release Planning Game, story card writing and estimating
• Iterations To First Release - Purpose: Implement a tested system ready for release. – Activities: testing, programming, Iteration Planning Game, task writing, estimating
• Productionizing - Purpose: Operational deployment. – Activities: documentation, training. marketing ….
• Maintenance - Purpose: Enhance, fix, build major releases. – Activities: May include these phases again for incremental releases
• These have been mapped to the UP phases for the purpose of this example
14Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
No Elaboration
This strategy is appropriate when: • Architecture is already proven and familiar• Requirements are known and of low technical risk• Team is experienced in the architecture and the domain• Project team is small; project is collaborative and informal
Time
Resources
Inception Construction Transition
Start Development Iterations / First Release
Date Agreed
Release Delivery
15Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Typical Iteration Patterns for Multiple Release
Incremental (3)
Evolutionary (1)
Incremental delivery (4)
Immediate Construction (2)
Time
Resources
Inception Elaboration
Const’n Transition
Conceptual Prototype
ArchitecturalBaseline
Delivery DeliveryDelivery Delivery Delivery DeliveryResources
TimeInception Elaboration
Construction Transition
Conceptual Prototype
ArchitecturalBaseline Release Delivery
Resources
TimeInception
Elaboration Const’n Transition
Conceptual
Prototype
ArchitecturalBaseline
Release Delivery
Time
Resources
Construction Transition
LCO and LCA
Passed
FirstRelease
Delivery
In practice you often end up with a hybrid, some evolution at the beginning, some incremental building, and multiple deliveries.
16Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Think:
• Among the advantages of the Unified Process phased iterative model is that it lets you accommodate a hybrid approach, simply by increasing the length and number of iterations in particular phases:
• For complex or unfamiliar problem domains, where there is a high degree of exploratory business work required: increase the length of, and the number of iterations in, the inception phase.
• For complex or unfamiliar technology problems, where there is a high degree of technological exploratory work required: increase the length of, and the number of iterations in, the elaboration phase.
• For more complex development technologies, where there is complexity translating the requirements and design into code: increase the length of, and the number of iterations in, the construction phase.
• To deliver software in a series of frequent incremental releases: increase the length of, and the number of iterations in, the transition phase.
17Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
How To Use The Iteration Patterns
• Think about your risks
• Think about your team’s skills and experience
• Think about where your project is in the lifecycle
• Select a pattern as a reference model– Don’t be scared to adjust the model
– You may require a hybrid pattern
18Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
How To Use The Numbers
• Use the numbers to challenge your plans and estimates– The numbers are for “typical projects”
– You should be able to explain why your project doesn’t conform
• The numbers for Inception and Transition carry least weight:– These can vary massively depending on the nature of the project
– These figures are not part of the COCOMO statistical model
• Elaboration should be small in comparison to Construction when considered across the entire endeavor– Architecture is the most important 20% of the development
– Elaboration may be relatively large in early project evolutions
The only thing we know for certain about yourproject is that it is not typical
19Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Some Hints and Tips
• Name Iterations – they have a theme• Number iterations within phases.• Make milestones real to the business• Give project a heartbeat• Be prepared to adjust iteration numbers and lengths
based on lessons learned• Anything beyond the next iteration is only a sketch
You cannot create a concrete plan until the end of Elaboration – there are too many unknowns
20Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Effort By Phase By Discipline
EIA StageInception
Development
TransitionElaboration Construction
Management 14% 12% 10% 14%
Environment / CM
10% 8% 5% 5%
Requirements 38% 18% 8% 4%
Analysis & Design
19% 36% 16% 4%
Implementation (Code & Unit
Test)8% 13% 34% 19%
Assessment 8% 10% 24% 24%
Deployment 3% 3% 3% 30%
Note: COCOMO II uses Design instead of Analysis and Design. Analysis is not mentioned in the breakdown.
21Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
What Gets Produced?
The Key Development Products
22Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
The 10 Essentials of RUP
1. Vision – Develop a Vision
2. Plan – Manage to the Plan
3. Risks – Identify and Mitigate Risks
4. Issues – Assign and Track Issues
5. Business Case – Examine the Business Case
6. Architecture – Design a Component Architecture
7. Product – Incrementally Build and Test the Product
8. Evaluation – Regularly Assess Results
9. Change Requests – Manage and Control Change
10. User Support – Provide Assistance to the User
Source: The Ten Essentials of RUP – The Essence of an Effective Development Process, Leslee Probasco, Rational Software White Paper
23Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Phase Review
• What to look for at a Phase Review– Why
– What
– When
– Who
– Where
– How
– How Much
The Phase Reviews are stakeholder decision points.A go / no go decision is made based upon the
business case, risks, progress and plans.
24Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Phases and Use Cases
Use-Case State
Inception Elaboration Construction Transition
Identified 60% > 80% 100% 100%
Outlined 50% 20% - 60% 0% 0%
Described 10% 40% - 80% 100% 100%
Analyzed < 10% * 20% - 40 % 100% 100%
Designed, Implemented and Verified
< 5% * < 10% 100% 100%
Source: Adapted from The Unified Software Development Process, Jacobson et al (page 358).
* A small percentage may be addressed for proof of concept purposes.
By the end of:
25Iterative Project Management / 04 - Phase Planning and Assessment© 2005 Ivar Jacobson International
Summary / Conclusion
• Each Phase is driven by a different set of forces– Inception – Business risks– Elaboration – Technical risks– Construction – Project logistical risks– Transition – Solution roll-out risks
• Each phase needs to be managed a little differently– Each phased requires a different mixture of skills and levels of resources; it is not unreasonable to expect that different teams may staff each phase so long as there is a
continuity of vision and expertise across phases
• Be rigorous about phase-end milestones– Do not move to next phase until you have met milestone objectives– Don’t be pressured by the schedule into “declaring victory” – you will pay for it later!