Efficiency metrics for a formal review are used to measure the cost-effectiveness of the review process, such as the time spent on the review, the number of defects found, and the return on investment1. These metrics can help to evaluate if the review was a good use of resources, such as human effort, money, and tools.
Therefore, option B is the correct answer. Option A is incorrect because efficiency metrics do not track who participated in the review, but rather how they performed. Option C is incorrect because efficiency metrics do not measure the quality of the reviewed object, but rather the quality of the review process. Option D is incorrect because efficiency metrics do not measure the speed with which defects were fixed, but rather the speed with which defects were detected. References: 1: How to manage formal reviews & management audits? Skills, metrics ...