Invested defect detection effort during the software inspection process. Inspection effort includes a) individual inspection effort and (b) team meeting effort for inspection meetings.

Biffl S., Halling M.: "A Knowledge Management Framework to Support Software Inspection Planning", In: Aurum A., Jeffery R., Wohlin C., Handzic M.: Managing Software Engineering Knowledge, Part 3, pp 231-249, Springer Berlin Heidelberg, 2003. [Springerlink]