When should you inspect software?

Research into Code Inspection
When should you inspect software?

We advise you to inspect code during development AND before testing:

Inspect during development—Software maintenance starts from day one of a project and inspected software is less expensive to alter, fix and maintain. This statement is founded upon these research findings:

Fixing defects early cuts costs in half,
Catching defects during testing is 10 times more expensive,
Debugging represents half of development costs,
90% of development work occurs after initial release,
25% of requirements change during development,
70% of rework caused by changing requirements.

Inspect before testing—Software should be inspected before it is tested: when it comes to finding defects, inspection is much cheaper and faster. This statement is founded upon these research findings:

Defect removal is the most expensive part of software process,
Inspection is 20 times more efficient,
Inspection is nearly twice as fast,
Inspection is 80% faster than testing,
Find design defects 6 times faster,
Inspection 4 to 7 times faster than testing.

Research into Code Inspection When should you inspect software?

Research into Code Inspection
When should you inspect software?