Presented by

Deep kumar sharma

M.Tech (1 sem)

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1. What is Defect Analysis2. Defect Prevention Key Process Area3. Defect Analysis Procedure4. Action Team Activities5. Summary

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• Examination of information about problems• Intent to identify causes of defects so that they can be

prevented or detected earlier Many different approaches called defect analysis or root

cause analysis – employ many different techniques Software

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• Error - a mistake made by a member of the software team• Defect - a section of code or documentation that must be changed

to correct a failure• Failure - a situation in which the software fails to execute as

intended• Problem Report - usually documentation that a failure has occurred

during testing or use. May also be used to document defects found in inspections and reviews.

Software Defect can be defined as “Imperfections in software development process that would cause software to fail to meet the

desired expectations”.

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3.The Defect Causal Chain

Defect(Quality)

Error(Process)

1 + 1 = 3

Failure(Reliability)

PumpingStation

OILCO

Accident(Safety)

OILCO

CausalAnaysisCausal

AnalysisDebuggingDebugging

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CausalAnalysis

ProcessAnalysis

ActionPlanning

ProjectSoftwareProcess

Data

Out of ControlSignal & Data

ProposedAction(s)

CorrectiveAction(s)

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• Assigns responsibility for causal analysis of a process to the software team

• Bases analysis on a sample of problems rather than an exhaustive study of all problems

• The software team proposes actions to:

– prevent problems

– find problems earlier• Assigns responsibility for implementing proposals to a

management action team

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CausalAnalysisMeeting

SoftwareEvaluation

SoftwareProduction

ProblemsIdentified

Software

ActionTeam

Meeting

ProblemDatabase

Sample ofProblems

RecommendedActions

Long-termActions

Problemsto Fix

Organization Process

Short-termActions

Baseline forFuture Projects

Improvement Cycle

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Purpose◦ To identify the cause of defects and prevent them from

recurring KPA goals

◦ Defect prevention activities are planned◦ Common causes of defects are sought out and identified◦ Common causes of defects are prioritized and systematically

eliminated

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Defect prevention is an important activity in any software project. In most software organizations, the project team focuses on defect

detection and rework.. It is therefore advisable to make measures that prevent the defect

from being introduced in the product right from early stages of the project

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Phase KickoffMeeting

CausalAnalysis

Team

ActionTeam

Project Phase (ongoing work)

Defects

SuggestedActions

Process Improvements

Improved ProcessesLessons Learned

Interim ProcessImprovements

Prepared Team

ProcessAssets

DP ActivityPlanning

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• Defines focus, composition, roles, and responsibilities of defect causal analysis team(s)

• Defines charter, composition, roles, and responsibility of action team(s)

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Type of Defect

Nu

mb

er

INTERFACE

DATALOGIC

INITIALIZATION

COMPUTATION

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Type of Defect

Rew

ork

INTERFACE

DATA

LOGIC

INITIALIZATION

COMPUTATION

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• Simple graphical technique• Helps to sort and relate many factors• Developed as a team (facilitated)• Focus for discussion - not a definitive result• Also called an Ishikawa or Fishbone Diagram

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• State problem (effect) - Use statement of Systematic Error - Draw main branch

• Insert headings for generic causes

– methods

– people

– tools/environment

– Input• Highlight principal/operative causes(s) - circle

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Misuse ofComputingEnvironment

Input Methods

People Tools

Lack of

Know

ledge

Lack

of

Con

vent

ions

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• Meets regularly to consider proposed actions • Must include management - needs resources• May include technical personnel • Select and prioritize proposals• Resolve conflicts and combine related proposals• Plan and schedule implementation• Allocate resources and assign responsibility • Monitor progress and effectiveness • Communicate actions and status to the teams

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design code function test system test

Nu

mb

er

of

De

fec

ts

Expected Trend

1.Example of ODC Trend

FunctionAssignmentCheckingTiming

Legend

ODC(Orthogonal defect classification) defect type process signature

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• Most organizations with well-defined processes can benefit from some application of DCA

• Maximum benefit obtained from

– Following a systematic approach

– Involving the developers/maintainers

– Pursuing a strategy derived from an objective understanding of improvement opportunities

• DCA can be applied to any process that receives feedback on its defects or failures

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Ajit Ashok Shenvi,2009,”Defect Prevention with Orthogonal Defect Classification”, In Proc- ISEC ’09, February 23-26, 2009 Defect Prevention by SEI’s CMM Model Version 1.1., http://www.dfs.mil/technology/pal/cmm/vl/dp Linda Westfall, Defect Density Mukesh soni, 1997, Defect Prevention: Reducing cost and improving quality” published in IEEE Computer, (Volume 30, Issue 8), August 1997.

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