1. SQA for Individuals based on
"A Personal Commitment to Software Quality"
by W.S. Humphrey
SEI at Carnegie Mellon University

2. Reasons for Looking at the Individual
The root cause of all software defects is humans.
Software productivity declines as product size increases.
Increased complexity makes debugging difficult, so more time is spent in testing.
If the all individual parts are of very high quality, your process can scale up with little reduction in productivity.

3. The Nature of Quality Most Important Second Most Important:
must provide necessary functions to the user
includes usability and convenience
Second Most Important:
the product must work
Distance Third…
compatibility,
and all the other "ilities"

4. Why Companies Don't do QA
Schedules built on unreliable data force developers to spend much time reacting to crises.
No time to do much if any QA
hence, biggest budget item is usually Testing
Stuck in rut of "test, debug, fix, repeat"
Experimenting is a risk
Developers have no data on the number of defects they inject or the costs of fixing those defects.

5. Costs of Defects Determining that there is a problem
Isolating the source of the problem
Determining exactly what is wrong
Fixing the Requirements
Fixing the Design
Fixing the Implementation
Inspecting and Testing the fix
Testing the fix to ensure it doesn't cause other problems
Changing the Documentation to reflect the fix

6. Real Cost Data IBM (relative costs)
during design $1.5
prior to coding $1
during coding $1.5
during test $60
in field use $100
Reviews are 2 or 3 times as efficient as testing at finding defects.
Combined design and code reviews have a yield of 60% to 80%.

7. Example Without any QA With Reviews
50 KLOC with 2500 defects to be found
average 4 hours of work per defect
10,000 hours to remove defects
With Reviews
50 KLOC with 2500 defects
70% of defects removed via Reviews
average 0.5 hours per defect
875 hours of work
remaining 750 defects
average 8 hours each
6000 hours
Total = 6,875 hours

8. Measures for Individuals
Failure Costs
total time in compile and test
few developers count defects found during compile and individual unit testing
Appraisal Costs
time spent in design and code reviews
any inspection time
Prevention Costs
prototype development
casual analysis meetings
process improvement actions or meetings

9. Measures for Individuals
Yield (step n) = 100 * (defects removed in step n)
(defects removed in n + defects escaping n)
Goals, perform small experiments to
improve the yield of filters
reduce the # of defects injected
improve productivity
measured in LOC produced per month
productivity increase comes from less time spent in testing