agile process models

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Agile Process Models. P rescriptive models dont work. It is unrealistic to not have changes. Why? The Agile Manifesto: Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation - PowerPoint PPT Presentation


Agile Process Models

Agile Process ModelsPrescriptive models dont workIt is unrealistic to not have changes. Why?The Agile Manifesto:Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan

The Agile approachFix time and resources, not featuresFunctionalityTimeResourcesFunctionalityTimeResourcesAgilePrescriptiveFIXEDVARIABLEThe Agile approachEffective and rapid response to changeEffective communication among all stakeholdersOn-site customerRapid, incremental delivery of softwareThe Agile processDriven by customer descriptions of what is desiredThese are translated into short-lived plansDevelopment is iterativeAdapts as changes occurLittle to no documentationWhy bother documenting what is likely to change?Customer is on-sitePopular Agile ProcesseseXtreme ProgrammingScrumeXtreme ProgrammingVery programmer-focused; take the good practices and do only those!Simplicity CommunicationFeedbackCourage

XP practices: PlanningBegins with customer-defined user storiesAgile team assigns each story a costStories are grouped into deliverable incrementsCommitment is made on delivery dateAfter the first increment this project velocity is used to define future increments

XP practices: planning gameWrite a Story(Customer)Spike a Story(Developer)Estimate a story(Developer)Split a Story(Customer)Sort stories by value(Customer)Declare velocity(Developer)ExplorationPlanningtoo bigdont know howXP practices: user storiesWatered-down version of use casesWritten by customers, estimated by developersOften on post-it notesReplaces large documents

XP practices: on-site customer

More XP practicesSmall releasesContinuous integrationImplies refactoringSystem metaphorSustainable pace40 hours max/week

XP practices: Pair programmingOne developer writes, the other watchesSwitch every two hoursResults in collective ownershipNeed a coding standardXP practices: Test Driven DevelopmentWrite automated unit tests first (will all fail)Only write code until all tests passStop there; no extra features!

When not to use XPCustomer requires documentationTeams larger than 15 peopleWhen you cant get immediate feedback (embedded systems)When its impossible to get people in the same roomScrumSprints, backlog, daily scrum meeting

Criticisms of Agile approachesLack of scalabilityRelies on mature teamMay result in inefficient designs due to incrementalityPotentially expensive On-site customerRework Inefficiency