Residual risk is the risk that remains after implementing controls to mitigate the inherent risk. A reduction in residual risk indicates that the information security program is effective in managing the risks to an acceptable level. This would best justify the continued investment in the program, as it demonstrates the value and benefits of the security activities. Security framework alignment, speed of implementation, and industry peer benchmarking are not direct measures of the effectiveness or value of the information security program. They may be useful for comparison or compliance purposes, but they do not necessarily reflect the impact of the program on the risk profile of the organization. References = CISM Review Manual, 16th Edition, page 431; CISM Review Questions, Answers & Explanations Manual, 10th Edition, page 622

Residual risk is the remaining risk after all security controls have been implemented. It is important to measure the residual risk of an organization in order to determine the effectiveness of the security program and to justify continued investment in the program. A reduction in residual risk is an indication that the security program is effective and that continued investment is warranted.