CS3100 Software Project Management Week 26 - Quality Dr Tracy Hall

Slide 2 Learning outcomes 1. To understand the wider implications of quality 2. To understand the options to monitor and control it

Slide 3 Triple Constraint.. again Time Budget Concentrated here so far Quality What about this?

Slide 4 What is Quality? …the totality of features and characteristics of a product or service that bears on its ability to satisfy stated or implied needs. American Society of Quality Degree to which a set of inherent characteristic fulfills requirements ISO 9000 Fitness for purpose Perceived Quality - Reputation

Slide 5 A wider view of quality Time Budget Quality Checks & feedback Inter- operability Ease of use Error-free use Clear interface Impact Liability Standards Profits Maintenance Compatibility Upgrades Reputation Marketing No bugs Well-coded Good design interfaces functions features reliability speed latency

Slide 6 Different perspectives PEOPLE End User Customer Managing Director Legal Team Developer What is quality from these perspectives

Slide 7 Cost of prevention amount spent to ensure work will be done correctly includes risk reduction and error prevention e.g. getting design right before production activities may include supplier evaluation, training and staff development Quality planning; formal technical reviews; test equipment; training Cost Defects Time What is the cost of quality? Amount

Slide 8 appraisal costs association with inspection and testing - company’s products - supplier’s products e.g. testing, walkthroughs, design reviews In-process and interprocess inspection; equipment calibration and maintenance; testing Cost Defects Time Other costs associated with quality

Slide 9 internal failure cost of putting everything right while project still under control (pre-delivery) re-coding software for problems found at internal testing Rework; repair; failure mode analysis external failure costs incurred post-delivery - warranty/support costs - maintenance - handling complaints lost future business Complaint resolution; product return and replacement; help line support; warranty work The killers

Slide 10 - A total of 7053 hours was spent inspecting 200,000 lines of code with the result that 3112 potential defects were prevented. - Assuming a programmer cost of $40.00 per hour, the total cost of preventing 3112 defects was $282,120, or roughly $91.00 per defect. - No inspections but that programmers had been extra careful and only one defect per 1000 lines of code escaped into the shipped product. That would mean that 200 defects would still have to be fixed in the field. - At an estimated cost of $25,000 per field fix, the cost would be $5 million, or approximately 18 times more expensive than the total cost of the defect prevention effort Internal failure External failure (Pressman 1997, p192) Costs of avoiding poor quality

Slide 11 Attributes portability completeness security efficiency reliability speed maintainability usability conciseness

Slide 12 How do we ensure quality? Is it about measurement and process? Can you measure quality? Do you just check for quality at the end?

Slide 13 Prioritising problems 80:20 Rule 80% problems stem from 20% sources Focus on the 20% first But don’t neglect the other 80%

Slide 14 V Model Quality Control throughout Software LifeCycle unit test integration test systems test acceptance test feasibility analysis design program specs coding Inspection stream Testing stream

Slide 15 Other Processes ISO 9000 CMMSoftware Engineering Institute Motorola TQM Six Sigma Look up some of these terms on the internet, academic papers etc.

Slide 16 ISO 9000 International Standard Focusess Documentation of Process Documentation of Proof of Process Requires Certification Re-Certification

Slide 17 corporate quality manual critical procedures manual - corporate - divisional - functional procedure guides documentationdetailed work instructions policy objectives organisation primary functions procedures index who does: what when how in what sequence Quality management system structure (Cadle & Yeates p240) Structure

Slide 18 planning a formal definition of how it will work provides key reference point for project team members acts as a bridge between customer and the supplier provides a discipline and offers a framework against which issues can be considered and addressed before and during a project. Quality Plans

Slide 19 CMM Capability Maturity Model Level 1 - Initial Unpredictable and Poorly controlled Level 2 - Repeatable Able to repeat previously mastered tasks Level 3 - Defined Process is understood Level 4 - Managed Process is measured and Controlled Level 5 - Optimizing Focus on process improvement

Slide 20 TQM Total Quality Management Total = Whole organisation Encourage culture of achieving and maintainting quality

Slide 21 Quality in 30 seconds Understand it Recognise the Causes Positive Negative Plan it: Work out how to measure it Work out how to make it happen Make it easy for your team to exhibit quality Implement it, and… …encourage a Culture for Quality