intorduction to lean software development...

l e a nsoftware development

www.poppendieck.comMary Poppendieck

Lean Software DevelopmentSpeed – Quality – Low Cost

February 052 Copyright©2004 Poppendieck.LLC l e a n

Principles of Lean Software Development

1. Eliminate Waste

2. Increase Feedback

3. Delay Commitment

4. Deliver Fast

5. Build Integrity In

6. Empower the Team

7. Optimize the Whole

Speed

Quality Low Cost


Principle 1: Eliminate Waste

Waste is anything that does not add customer valueWaste is anything that does not add customer valueCustomers wouldn’t choose to pay for it.

Waste is anything that has been startedbut is not being used in production.

Waste is anything that delays developmentor keeps people waiting.

Waste is any extra features that are not needed now.

Waste is making the wrong thingor making the thing wrong.


Myth 1: Early Specification Reduces Waste

Features and Functions Used in a Typical System

Standish Group Study Reported at XP2002 by Jim Johnson, Chairman

Always7%

Often13%

Sometimes16% Rarely

19%

Never45%

Rarely or NeverUsed: 64%

Often or AlwaysOften or AlwaysUsed: 20%Used: 20%


Principle 2: Increase Feedback

One Year Later….

Poor productivityPoor market acceptancePoor expert quality rating

Great market success

Alan MacCormackHarvard Business School

A Tale of Two Projects

Not ConsistentModify Hypothesis

ConsistentPublish Results

New Knowledge

Obser-vations

Predic-tionsTests

Hypothesis


Myth 2: Predictions Create Predictability

Increase predictability by not predicting. A plan is a guess, a track record is fact.

Reduce response time so you can respond to events rather than predict them.

Make decisions based on facts, not forecasts.

Reliability is not the same thing as predictability.Reliability is not the same thing as predictability.High reliability organizations are preoccupied with the unexpected.

See Managing the Unexpected: Assuring High Performance in an Age of Complexity by Karl E. Weick and Kathleen M. Sutcliffe


Principle 3: Delay Commitment

Pilots“In Pilot training, we learned that when we had to make a decision, we should first decide when the decision should be made, then when the time comes, make the decision based on the available information.”

Military“One of the most important thing I taughtyoung recruits is that when they were threatened,

they should decide on the timebox for a response, and not respond until the end of the timebox.”


Myth 3: Decisiveness is a Virtue

The Structure of Scientific Revolutions

Thomas Kuhn

Decisive people can’t shift their viewpoint.

“Invention is destroyed by decisiveness. The moment I close off possibility, I lose the option of seeing a better way.”

John Lienhard


Principle 4: Deliver Fast

Rapid Delivery is the Competitive Advantage of:

Competing on the basis of time providesSignificant competitive advantageLarge barrier to entry

Order Processing

Supply Chain Product Development

ShippingManufacturing

Aircraft Turnaround


Myth 4: Increase Utilization

To go faster you canIncrease the average completion rate

Requires financial capital

Reduce the number of things in the pipelineRequires intellectual capital

Total Cycle Time =Number of Things in Process

Average Completion Rate

Conquering Complexity in Your BusinessBy Michael George and Stephen Wilson


Principle 5:Build Integrity In

1. Organized WorkspaceCleanOrganizeSystemizeMaintainSustain

2. Standardized Infrastructure• Architecture• Conventions

– Naming– Coding– GUI– Security– Etc.

3. Configuration Management4. Automated Tests5. One Click Build6. Continuous Integration

STOPSTOP if the tests don’t pass!

7. Automated ReleaseMistake Proof Installation

8. Refactoring Pay down technical debt

Building Block Building Block DisciplinesDisciplines


Myth 5: Get it Right the First Time

Iteration generates waste (rework)Iteration generates learning

Variability of outcomes is not desirable.

Variability of outcomes is desirable

Quality is conformance to requirements(which were determined during design)

Quality is fitness for use(realization of purpose)

Produces the DishProduces the DishDesigns the RecipeDesigns the Recipe

ProductionDevelopment


Principle 6: Empower the Team

Crisis at our Video Cassette PlantCompetition selling cassettes for less than we could make them

Our ResponseJust-in-Time (Lean) Production

The Great Coffee Cup SimulationPlant Manager, Materials Control Manager, IT Manager (me)Add Production General Managers Add General SupervisorsAdd Shift SupervisorsAdd Shift Workers

The Result Entire plant switched to pull scheduling over one weekendPack-out went from 60% to 95% the first weekEmployees said this was the best thing that happened to the plant


Myth 6: There is One Best Way

Frederick Winslow Taylor: Grandfather of the Process Police

Taylor’s View of EfficiencyEmployers get higher profits Workers get higher pay

But Scientific ManagementAffronts human dignity Discourages worker creativity


Principle 7: Optimize the Whole

Vicious Cycle #2:Vicious Cycle #2:1. Testing is overloaded with work2. Result: Testing occurs long after coding3. Result: Developers don’t get immediate feedback4. Result: Developers create more defects5. Result: Testing has more work. Systems have more defects.6. Result: Feedback to developers if delayed further. Repeat cycle.

Vicious Cycle #1:Vicious Cycle #1:1. A customer wants some new features yesterday2. Developers hear: Get it done fast, at all costs!3. Result: Sloppy changes are made to the code base4. Result: Complexity of code base increases5. Result: Number of defects in code base increases6. Result: Exponential increase in time to add features


Myth 7: Optimize through Decomposition

DecompositionYou get what you measureYou can’t measure everythingStuff falls between the cracksYou add more measurementsYou get local sub-optimization

ExampleMeasure Cost, Schedule, & Scope

Quality & Customer Satisfaction fall between the cracksMeasure these too!

AggregationYou get what you measureYou can’t measure everythingStuff falls between the cracksYou measure UP one levelYou get global optimization

ExampleMeasure Cost, Schedule, & Scope

Quality & Customer Satisfaction fall between the cracksMeasure Business Value with P&L or ROI instead

From to ! From to !


Financial Model

Software by Number by Mark Denne and Jane Cleland-HuangSelf-Funding

Breakeven

Inve

stm

ent

Pay

back

Pro

fit

Time

Cos

t


Staged Releases

Time

Cos

t

Release 1 ProfitRelease 2 Profit

Total Profit


Increase Business Value

Time

Cos

tProfit

Investment

Bre

akev

en

Single Release

Sel

f-Fun

ding

Bre

akev

en

Software by Number by Mark Denne and Jane Cleland-Huang

StagedReleases

l e a nsoftware development

www.poppendieck.comMary Poppendieck

Thank You!More Information: www.poppendieck.com

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