How to Jump-Start Inspection by Outsourcing


compatibility by countering the objection "We have no time for this," complexity by countering the objection "We don't have the resources," and the trialability objection "The investment is too high."

Makes testing more effective. By finding nasty defects such as NULL pointer dereferences and uninitialized variables before testing, there will be fewer disruptions of functional testing, so your functional testing will be more effective. This addresses the complexity concern "How can this be better, faster, and cheaper?" by showing where time can be gained downstream..

Independent third-party perspective. Every programmer's work is judged against the same standard by a third party that has no investment in the code generation. This is considerably less threatening than the prospect of having your work taken apart by a colleague, and thus addresses two relative advantage objections: fear of being exposed and fear of losing control .

Finds defects that testing misses. A research group at a large European corporation performed an independent validation of the effectiveness of outsourced inspections by outsourcing inspection of an embedded application that had already been inspected in-house and unit tested. The subsequent outsourced inspection revealed thirteen heretofore undetected defects, of which eleven needed to be fixed. This addresses all three objections under observability:  overconfidence in testing effectiveness , overconfidence in testing tools , and misunderstood responsibilities .

Closes the feedback loop. When people are confronted with their failings, their natural instinct is to take measures to prevent any future recurrence. A typical situation in dysfunctional software development organizations is that junior programmers are inadvertently inserting defects into code while senior developers are busy tracking down and fixing previously inserted defects. Outsourced inspection encourages the reverse situation, where experienced developers are freed up to focus on new coding while their less experienced colleagues can learn by fixing the defects identified as a result of the
inspection process. Like the previous item, this addresses all three objections
under observability.

Handoff creates quality data. An important component of the inspection process is measuring the numbers of defects found during inspections. Because the outsourced inspection process does not fix the defects, but only reports on them, the organization is presented with documentation supporting the measurement of numbers of defects, defect distributions, and trends. The handoff also increases compatibility by handling the objections we don't want to touch our process and fear of bureaucracy .

There are many steps critical to improving the quality of the software you're developing, such as introducing requirements and design inspections. At a minimum, though, outsourced code inspections should show the value of early defect detection without a huge up-front time and resource investment. Once your organization is used to an independent third party examining its code, the barriers to having peers inspect each other's code should also be lower.

Acknowledgments. I'd like to thank Chris Verhoef for pointing out the relevance of Diffusion Research to understanding the slow adoption of inspection, and Pat Bitton, Lawrence Markosian and Rix Groenboom for numerous useful suggestions.


  • Robert L. Glass, "What's so Great About Inspections?!?" 8 June 2001.
  • Oliver Laitenberger and Jean-Marc DeBaud, "An Encompassing Life-Cycle Centric Survey of Software Inspection," ISERN-98-32.
  • Rix Groenboom and Walter Loeffel. "Automated Software Inspection," Informatik, Feb. 2001.

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