NetNews Usenet Archive 1992 #26/NN_1992_26.iso/spool/comp/software/4188

Internet Message Format | 1992-11-08 | 1.7 KB

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From: [e-mail]. (Peter Spool)
Newsgroups: comp.software-eng
Subject: Defect Costs
Message-ID: <prspool.721000280@terra>
Date: 5 Nov 92 21:51:20 GMT
Sender: [e-mail]
Lines: 34

The closest I've seen to a recent assessment of "Defect Costs"
was a presentation on the "Cost of Quality" by Ray Dion of the Raytheon
Equipment Division. The talk was given at the Software Engineering Symposium
in Pittsburgh this past September.   He tracked three categories of costs:

1. Appraisal Costs: which included Reviews, Walkthroughs, Inspections,
   Testing (the FIRST time), Independent Verification and Validation
   (the FIRST time), and Audits.

2. Prevention Costs: which included Training, Tools, Mehtodologies,
   Policies and Procedures, Planning, Data Gathering and Analysis,
   Quality Improvement Projects, Fault and Root Cause Analysis.

3. Cost of Non-Conformance: Re-reviews, Re-tests, Fixing Defects in
   Code and Documentation, Engineering Changes, and Patches to Delivered Code.

Total Cost of Quality = Appraisal Costs + Prevention Costs +
                        Cost of Non-conformance

Over a three year period, the Cost of Quality went from about 60% of the
total product cost, to about 40%.  The savings were about $20 million.

Unfortunately, there was no mention during his talk, of the rate of
increase in cost to fix defects as time goes on.

I would be interested in hearing from others with information from
similar studies.


Peter R. Spool
Siemens Corporate Research
Princeton, NJ
[phone]
[e-mail]