Transcript PNSQC Tutorials

The "Two Engine Model" for Software
Quality Measurement and
Improvement
A lively romp through process capability,
documentation, and measurement without getting your
feet wet.
By
Tom Gilchrist
SASQAG, Aug 2011
Tom Gilchrist, [email protected]
Disclaimer
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Tom Gilchrist, [email protected]
The views and opinions in this
presentation are my own and
do not necessarily reflect
those of my employer….
Context is everything…your
mileage may vary.
If you don’t try something
different, don’t be surprised
that the outcome doesn’t
change!
Communication with an engineering is only a
little more difficult than communication with
the dead.
Tonight...
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Some Context
Feedback Systems
Change or Improvement?
Tom Gilchrist, [email protected]
Some Definitions….
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Process: How we remember things that
work, so we can repeat them. How we
remember things that don’t work, so we can
avoid them.
Errors, Defects, Faults, and Failures
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Error: a human action or mistake that results in the
SW containing a defect. (MEWU)
Defect: a Fault that exists in the software, which if
not corrected, could cause the software to fail or
produce incorrect results
Failure: An occurrence of the SW not meeting its
requirements or intended usage while it is being
executed.
Tom Gilchrist, [email protected]
Quality Measurement Areas
Pre-Development Errors
Requirements
Change Board
Subs
COTS
Design
Development Errors/Defects
Coding
Dev Tests
Pre-Release Failures
Int Tests
Acceptance
Post-Release Failures
Tom Gilchrist, [email protected]
Production
Quality Measurement Areas
Escape Rates, Efficiency & Effectiveness
Pre-Development Errors
Requirements
Change Board
Subs
COTS
Design
Development Errors/Defects
Coding
Dev Tests
Pre-Release Failures
Int Tests
Acceptance
Post-Release Failures
Tom Gilchrist, [email protected]
Production
Understanding Rework
Productivity
People
Quality
Work
Being
Done
WORK
TO BE
DONE
WORK
REALLY
DONE
Why is rework bad?
KNOWN
REWORK
UNKNOWN
REWORK
Rework
Discovery
*From IEEE Engineering Management Review, Winter 1994
Tom Gilchrist, [email protected]
Single Engine Model
Business
Objectives &
Constraints
Trigger
CONTROL
CYCLE
ACTION
Entry Criteria
Internal
Usage Results
MEASUREMENT
Exit
Criteria
PROCESS
Needs &
Constraints
Tom Gilchrist, [email protected]
Deliverables
Two Engine Model
Maintain and Improve
the Process
Results
Lessons
Learned
Organization
Professional Practices
Projects
Use the Process
Tom Gilchrist, [email protected]