1. Software Defect Reduction Top 10 List Barry Boehm, University of Southern California Victor R. Basili, University of Maryland IEEE Computer, January Eliminating Embedded Software Defects Prior to Integration Test Ted L. Bennett and Paul W. Wennberg Crosstalk, Dec

2. Top 10 List ONE – Effort to find and fix
Finding and fixing a software problem after delivery is often 100 times more expensive than finding and fixing it during the requirements and design phase
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3. Top 10 List TWO – Amount of avoidable rework
Current software projects spend about 40 % to 50 % of their effort on avoidable rework.
THREE - Defects causing rework
About 80 % of avoidable rework comes from 20 % of the defects.
FOUR - Modules contributing to defects
About 80 % of the defects come from 20 % of the modules, and about half the modules are defect free.
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4. Top 10 List FIVE – Defects contributing downtime
About 90 % of the downtime comes from, at most, 10 % of the defects.
SIX –Contribution of peer reviews
Peer reviews catch 60 % of the defects.
Peer review provides an effective technique that catches from 31 to 93 % of the defects, with a median of around 60 percent.
Peer reviews, analysis and testing catch different classes of defects at different point in the development cycle
SEVEN – Contribution of perspective-based reviews
Perspective-based reviews catch 35 % more defects than non directed reviews.
The union of several perspectives into a single inspection offers broad yet focused coverage of the document being reviewed.
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5. Top 10 List EIGHT –Contribution of disciplined personal practices
Disciplined personal practices can reduce defect introduction rates by up to 75 %. (PSP, TSP)
NINE – Cost of high dependability
All other things being equal, it costs 50 % more per source instruction to develop high-dependability software products than to develop low-dependability software products
TEN –Software quality at delivery
About 40 to 50 % of user programs (e.g. spreadsheet) contain nontrivial defects.
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6. Jet Propulsion Lab - Root-Cause Analysis of
Spacecraft Software Defects
Fault Distribution
Internal faults are defined as coding faults
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Bennett, T.L., Wennberg, P.W., Eliminating Embedded Software Defects Prior to Integration Test, Crosstalk, Journal of Defence Software Engineering, December 2005.

7. Relative cost of software fault propagation
Economics of Fault Finding
Relative cost of software fault propagation
368
400
Relative
Relative
Cost to
Cost to
350
Repair
Repair
300
250
130 64
200 37
150 50 7 26 3 13
100 10 10 3
Customer
Customer 5 1 2 1 5
Integration 1 50 1
Test 1
Phase
Defect
Repaired
Code
Design
Reqts
Reqts
Design
Design
Code
Code
Requirements
Test
Test
Integration
Integration
Phase Defect Introduced
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Bennett, T.L., Wennberg, P.W., Eliminating Embedded Software Defects Prior to Integration Test, Crosstalk, Journal of Defence Software Engineering, December 2005.