Iterative Project Management Chapter 7.2 – Evolution and Phase Planning Modified considerably by your Instructor

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


Planning an Evolution:Iteration Patterns – To show different Strategies…

• Incremental Development• Evolutionary Development• Incremental Delivery• Extreme Programming / No Elaboration• Immediate Construction / Virtual Phases


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

•


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


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

•


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



Release Delivery


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


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



Delivery DeliveryDelivery Delivery Delivery Delivery


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.


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


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.


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


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


Typical Iteration Patterns for Multiple Release

Incremental (3)

Evolutionary (1)

Incremental delivery (4)

Immediate Construction (2)

Time

Resources

Inception Elaboration

Const’n Transition



Delivery DeliveryDelivery Delivery Delivery DeliveryResources

TimeInception Elaboration



ArchitecturalBaseline Release Delivery

Resources

TimeInception

Elaboration Const’n Transition

Conceptual

Prototype


Release Delivery

Time

Resources


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.


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.


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


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


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


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.


What Gets Produced?

The Key Development Products


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


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.


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:


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!

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Iterative Project Management Chapter 7.2 – Evolution and Phase Planning Modified considerably by your Instructor