Defect Removal Efficiency (DRE)
DRE is a measure to detect defects before delivery.It is calculated as a percentage of the defects identified and corrected internally with respect to the total defects in the complete project life cycle. Thus, DRE is the percentage of bugs elimiated by reviews, inspections, tests etc.
Here is an interesting Defect Removal Efficiency calculator by Harvey Roy Divinagracia:
http://www.engin.umd.umich.edu/CIS/course.des/cis525/java/f00/harvey/DRE_Calc.htm