What is Software Development Quality?

1
What is Software Development Quality?
2
The Software Quality Landscape

• Characteristics of Software Quality
• Techniques for Improving Software Quality
• The General Principle of Software Quality

3
Dimensions of quality
Software Quality has elements of both
Manufacturing and Service Quality
4
Symptoms of unacceptable quality

• Crises, Firefighting, Stress.
• Overload, Backlog, No time to do things properly
• Errors when programs changed, can't confidently
  change things
• Poor Scheduling - Promises not kept

5
Relative Cost of Change

• Later Change is MUCH more expensive

How many organisations know the cost of defect
removal?
6
Customer-Oriented Quality

• Total quality means completely satisfying
  customers on the full range of product and
  service needs.
• We must define quality in terms of customer
  satisfaction.
• Quality management must first be
  customer-directed.
• Internal quality is not much use unless it links
  to customer-perceived quality.

7
What must we do?

• Identify and measure customer needs, and
• Link customer satisfaction measures to internal
  process measures
• Improvements in quality dont show up in market
  share, , for some time

8
How do we create quality?

• More pressure, stress, wont do it
• We must find more efficient ways of working
• Upgrade our process!
• Change our way of thinking!

9
Fix the Process

• Were good people
• Were trying hard
• Its not working
• gt FIX THE PROCESS

10
Common Fallacies

• We must start with firm requirements
• If it passes test, it must be OK
• Software Quality cant be measured
• The problems are technical
• We need better people
• Software Management is Different

11
Is this how to fix a problem?
From Controlling Software Projects, by Tom
DeMarco
12
Whats different?
From Controlling Software Projects, by Tom
DeMarco
13
Process Maturity Levels
PROCESS CONTROL
OPTIMIZING
MANAGED
PROCESS MEASUREMENT
DEFINED
PROCESS DEFINITION
REPEATABLE
BASIC MANAGEMENT CONTROL
INITIAL
CHAOTIC
From Managing the Software Process, by Watts S.
Humphrey
14
Making service quality financially accountable.

• Quality is an investment
• Quality efforts must be financially accountable
• It is possible to spend too much on quality
• Not all quality expenditures are equally valid.

15
Making service quality financially accountable (2)

• gt We need to involve our customers in defining
  Quality, so that we can improve our systems in
  ways that improve quality AS THEY PERCEIVE IT.
• gt We need to understand (including measurement)
  our present processes, so that-
• We can measure any improvements
• We can communicate more effectively with our
  customers (sell our successes!)

16
Where to start

• Establish baseline
• TQM - Involve EVERYBODY in improvement program
• Experiment, measure, LEARN

17
Review

• To Improve quality, we must change our PROCESS,
  in ways that increase customer satisfaction
• To know what/how to change our process, we need
  to know
• where were going
• where we are
• What we measure should relate to things that
  increase customer satisfaction