Unit 4: Quality management
Software Testing and Quality Assurance notes · PTU syllabus (BSIT602)
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Unit summary
Quality management systems make quality repeatable across projects. This unit covers ISO 9000 and ISO 9001, the Capability Maturity Model and its key process areas — requirements management, project tracking, configuration management, process definition, product engineering, peer reviews, quantitative process management and defect prevention — and Six Sigma.
After this unit you can
- Explain ISO 9000 and ISO 9001 for software
- Explain CMM levels
- Describe the key process areas
- Explain Six Sigma for software
PTU syllabus topics
- Quality standards (ISO 9000/9001, CMM, Six Sigma)
- CMM development and key process areas — requirements management
- software project tracking
- configuration management
- process definition
- product engineering
- peer reviews
- quantitative process management
- defect prevention
- 5. Optimising
Continuous process improvement
- 4. Managed
Measured quantitatively
- 3. Defined
Standard organisation-wide process
- 2. Repeatable
Basic project management
- 1. Initial
Ad hoc and chaotic
Topic 1
ISO 9000 and ISO 9001
- ISO 9000 family: ISO 9000 (fundamentals and vocabulary), ISO 9001:2015 (requirements — the certifiable standard), ISO 9004 (sustained success), ISO 19011 (auditing).
Customer focus
Leadership
Engagement of people
Process approach
Improvement
Evidence-based decision making
Relationship management
- Structure (high-level structure): context, leadership, planning (risk-based thinking), support, operation, performance evaluation, improvement — PDCA.
- Certification: by accredited third-party bodies (in India, accreditation by NABCB).
- For software: ISO/IEC/IEEE 90003 gives guidance on applying ISO 9001 to software; related standards include ISO/IEC 12207 (software life cycle processes) and ISO/IEC 25010 (product quality).
Origin
International Organization for Standardization
Software Engineering Institute, Carnegie Mellon University
Scope
Any industry
Software and systems development
Result
Pass or fail certification
Maturity level 1 to 5
Emphasis
Minimum quality system requirements
Continuous process improvement
Topic 2
The Capability Maturity Model
- Developed by the SEI (1991, Watts Humphrey) to assess and improve software process maturity; succeeded by CMMI (now maintained by ISACA's CMMI Institute).
- Level 5 Optimising
Continuous process improvement; defect prevention
- Level 4 Managed
Process and product quality measured quantitatively
- Level 3 Defined
Standard organisation-wide process
- Level 2 Repeatable
Basic project management; earlier successes repeated
- Level 1 Initial
Ad hoc, chaotic; success depends on individuals
Topic 3
Key process areas
Level 2 Repeatable
Requirements management, software project planning, software project tracking and oversight, subcontract management, software quality assurance, software configuration management
Basic project control
Level 3 Defined
Organisation process focus, organisation process definition, training programme, integrated software management, software product engineering, intergroup coordination, peer reviews
Standard engineering and management process
Level 4 Managed
Quantitative process management, software quality management
Quantitative control
Level 5 Optimising
Defect prevention, technology change management, process change management
Continuous improvement
Topic 4
Selected key process areas explained
- Requirements management
- Baseline requirements and control changes so plans and work stay consistent with them
- Software project tracking and oversight
- Compare actual progress with plans; take corrective action
- Software configuration management
- Identify configuration items, control and record changes, audit baselines — version control
- Organisation process definition
- Develop and maintain a standard software process and assets
- Software product engineering
- Perform engineering tasks consistently to produce correct, consistent products
- Peer reviews
- Remove defects early through structured reviews of work products
- Quantitative process management
- Control process performance statistically
- Defect prevention
- Find root causes of defects and prevent their recurrence
Topic 5
TQM and Six Sigma
- Total Quality Management (TQM): a company-wide approach to continuous quality improvement focused on customer satisfaction, involving everyone. Principles: customer focus, continuous improvement (Kaizen), employee involvement, process approach, fact-based decisions and supplier partnerships. Deming's PDCA cycle (plan-do-check-act) drives improvement.
- Six Sigma: a data-driven method to reduce variation and defects to 3.4 defects per million opportunities, using DMAIC — Define, Measure, Analyse, Improve, Control. Experts are certified as Green Belts and Black Belts.
Topic 6
Six Sigma for software
- 1Define
Problem: 20% of releases cause production incidents
- 2Measure
Collect defects per release and causes
- 3Analyse
Root cause — insufficient regression testing
- 4Improve
Automate regression suite; peer review checklist
- 5Control
Track defect escape rate on a control chart
- DMADV (Define, Measure, Analyse, Design, Verify) is used to design new processes or products. Sigma level: 6σ means 3.4 defects per million opportunities; 3σ about 66,800.
Key terms
- ISO 9001
- Certifiable standard for quality management systems
- CMM
- Five-level model of software process maturity
- Key process area
- Cluster of related activities achieving goals at a maturity level
- Configuration management
- Controlling changes to software work products
- DMAIC
- Define, Measure, Analyse, Improve, Control
Quick revision
- ISO 9000 family; 7 principles; ISO 9001 structure; ISO 90003 for software.
- ISO 9001 vs CMM.
- CMM levels 1–5; CMMI.
- KPAs at levels 2, 3, 4 and 5.
- TQM; Six Sigma, DMAIC, DMADV; 3.4 DPMO.
Important exam questions
Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).
Short-answer questions
- Q1.What is ISO 9001?
- Q2.Name the five CMM levels.
- Q3.Name two KPAs at level 2.
- Q4.What is software configuration management?
- Q5.Expand DMAIC.
- Q6.How many defects per million does Six Sigma allow?
Long-answer questions
- Q1.Explain ISO 9000 standards for software quality.
- Q2.Explain the Capability Maturity Model and its levels.
- Q3.Explain the key process areas of CMM.
- Q4.Explain Six Sigma and its application to software.
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