Software Quality & Process Improvement
Dr. Ita Richardson
Lero – the Irish Software Engineering Research Centre
and Department of Computer Science & Information Systems
University of Limerick
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1
LECTURE 1:
SOFTWARE QUALITY WITHIN TOTAL
QUALITY MANAGEMENT
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Software Quality
• Define Software Quality within framework
of Total Quality Management
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What is Quality?
VS
VS
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What is Quality?
• Three dimensions to quality:
– Quality of the product
– On-time delivery
– Cost
• Producer match competitor in any two and beat them in
the third, then they have competitive advantage
» Calloway & Chadwell, 1990
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“Good-Enough Software”
Software cycle-time
& its predictability
Software
functionality
“Good-enough
Software”
SW dev’t productivity / predictability
SW process capability & maturity
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Software
quality
TOTAL QUALITY MANAGEMENT
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Total Quality Management
•
•
•
•
Fitness to Standard
Fitness to Use
Fitness of Cost
Fitness to Latent Requirement
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Fitness to Standard
Company Focus
Customer Focus
Standardisation
Statistical Process Control
Inspection
Fitness to standard
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Fitness to Standard - Software
• Statistically based measurements
• Errors per line of code:
Number of Defects Discovered
Number of lines of code
• Readability - Fog Index:
0.4 * No of words in sentence
+ % of words with more than two syllables
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“Good-Enough Software”
• Fitness to Standard:
– What metrics do we use?
– What are our limits and controls?
– “Testing is emphasised as a verification
technique”
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Fitness to Use
Company Focus
Customer Focus
Standardisation
Statistical Process Control
Inspection
Fitness to standard
Market research
Cross-functional involvement
Fitness to use
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Fitness to Use - Software
• "The hardest single part of building a software
system is deciding precisely what to build... No
other part of the work so cripples the resulting
system if it is done wrong. No other part is more
difficult to rectify later.”
– Fred Brooks Jr. "No Silver Bullet" 1986
• Quality of Use
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Requirements Engineering
• “The development and use of cost-effective
technology for the elicitation, specification
and analysis of the stakeholder
requirements which are to be met by
software intensive systems”
– Berry and Ryan, 1999
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Quality of Use
• Can computer systems be used
– by the novice?
– by the subject expert?
• Usability issues
• Efficiency issues
• Outstanding errors
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“Good Enough Software”
• Fitness to Use:
– How do we gather requirements?
– How important are requirements from the ‘gemba’?
– Does it matter whether the customer can use our product
efficiently?
– How do we determine this?
– “No company uses requirements gathering models”
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Fitness of Cost
Company Focus
Customer Focus
Standardisation
Statistical Process Control
Inspection
Fitness to standard
Market research
Cross-functional involvement
Fitness to use
QC Circle
7QC steps, 7 QC tools
= improvement methods
Fitness of cost
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Fitness of Cost - Software
• Development costs
• High cost of testing
• Maintenance costs
• Focus on Software Process
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Software Process Models
• Capability Maturity Model
• Software Process Improvement and Capability
dEtermination (ISO15504)
• ISO9000 (not strictly Software Process)
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“Good Enough Software”
• Fitness of Cost
–
–
–
–
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Can we reduce the cost of production?
Will this affect the quality of the product?
Does improving the software process actually reduce cost?
“Improving the process improves the quality of the product; it
also improves implementation and maintenance”
Fitness to Latent Requirement
Company Focus
Customer Focus
Standardisation
Statistical Process Control
Inspection
Fitness to standard
Market research
Cross-functional involvement
Fitness to use
QC Circle
7QC steps, 7 QC tools
= improvement methods
Fitness of cost
QFD
7 Management Tools
Fitness to latent
requirement
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Fitness to Latent Requirement
• Determining customer requirements even
though customer does not realise they have
them
• Seven management and planning tools
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Latent Requirements - Software
• Requirements Engineering carried out using
Quality Function Deployment and the
Analytic Hierarchy Process
» Karlsson and Ryan, 1997
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“Good Enough Software”
• Fitness to Latent Requirement
– Can we establish latent requirements?
– Is it cost-effective to do so?
– Can we gain competitiveness through establishing
latent requirements?
– “.. The requirements actually selected for
implementation have a profound impact on the final
product”
» Karlsson
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Total Quality Management
Company Focus
Customer Focus
Standardisation
Statistical Process Control
Inspection
Fitness to standard
Market research
Cross-functional involvement
Fitness to use
QC Circle
7QC steps, 7 QC tools
= improvement methods
Fitness of cost
QFD
7 Management Tools
Fitness to latent
requirement
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TQM & Software
• Fitness to Standard
– Metrics
• Fitness to Use
– Requirements Engineering
• Fitness of Cost
– Software Process
• Fitness to Latent Requirement
– Methods for latent requirement collection
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Software Quality
• Software Quality has been defined within
the framework of Total Quality
Management
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Acknowledgements
•
The information presented in these slides has been collected from a variety of sources
including:
– Software Quality Assurance: From Theory to Implementation by Daniel
–
–
–
–
•
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Galin, 2003
Software Process Improvement: Practical Guidelines for Business Success by Sami Zahran, 1998
Research carried out by post-doctoral researchers and PhD students at Lero – the Irish Software
Engineering Research Centre, Ireland under the supervision of Dr. Ita Richardson
Software Process: Improvement and Practice (journal)
The SPIRE Handbook: Better, Faster, Cheaper Software Development in Small Organisations,
edited by Marty Sanders (Version 1, 1998) and Jill Pritchet (Version 2, 2000)
The research presented in this lecture has been partially supported by Science
Foundation Ireland funded through Global Software Development in SMEs Cluster Grant
(no 03/IN3/1408C) and Lero – the Irish Software Engineering Research Centre (CSET
grant no 03CE2/I303.1).
References
• Calloway, Dave and Brain Chadwell, 1990. "Manufacturing Strategic Plan QFD and the Winchester Gear Transfer", Transactions from the Second
Symposium on Quality Function Deployment, Novi, Michigan, U.S.A., June
8-10th, 1990, pp 370-380.
• Brooks Jr, Fredrik P., 1986. “No Silver Bullet – Essence and Accidents of
Software Engineering”, Information Processing, pp 1069-1076.
• Berry, Daniel M. and Kevin Ryan, 1999. Presentation in RENOIR URL
www.cs.ucl.ac.uk/research/renoir, Requirements Engineering Network of
International Co-operating Research Groups, Accessed in July, 1999.
• Karlsson, J and Ryan, K, 1997. A Cost-Value Approach for Prioritizing
Requirements, IEEE Software, Volume 14, Issue 5 pp. 67 - 74
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