Catching defects during testing is 10 times more expensive

Research Finding:
Construction errors detected during system testing cost 10 times more to fix than in the construction phase and 10-25 times more to fix when detected post-release.

Sources:

Cover of IBM Systems Journal Design and Code Inspections to Reduce Errors in Program Development
Cover of Managing the Software Process Managing the Software Process
Cover of American Programmer Calculating the Return on Investment from More Effective Requirements Management
Cover of Software Engineering Institute Hughes Aircraft's Widespread Deployment of a Continuously Improving Software Process
Presentation An Economic Release Decision Model: Insights into Software Project Management
Presentation What We Have Learned About Fighting Defects
Cover of Balancing Agility and Discipline: A Guide for the Perplexed Balancing Agility and Discipline: A Guide for the Perplexed
Cover of Professional Software Development Professional Software Development