Understanding the Sources of Variation in Software Inspections

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Date
1998-10-15Author
Porter, Adam A.
Siy, Harvey
Mockus, Audris
Votta, Lawrence G.
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Show full item recordAbstract
In a previous experiment, we determined how various changes in three
structural elements of the software inspection process (team size, and
number and sequencing of session), altered effectiveness and interval.
our results showed that such changes did not significantly influence the
defect detection reate, but that certain combinations of changes
dramatically increased the inspection interval.
We also observed a large amount of unexplained variance in the data,
indicating that other factors much be affecting inspection performance. The
nature and extent of these other factos now have to be determined to ensure
that they had not biased our earlier results. Also, identifying these
other factors might suggest additional ways to improve the efficiency of
inspection.
Acting on the hypothesis that the "inputs" into the inspection process
(reviewers, authors, and code units) were significant sources of variation,
we modeled their effects on inspection performance. We found that they
were responsible for much more variation in defect detection than was
process structure. This leads us to conclude that better defect detection
techniques, not better process structures, at the key to improving
inspection effectiveness.
The combined effects of process inputs and process structure on the
inspection interval accounted for only a small percentage of the variance
in inspection interval. Therefore, there still remain other factors which
need to be identified.
(Also cross-referenced as UMIACS-TR-97-22)