The primary basis for establishing metrics that measure the effectiveness of an information security program should be the risk tolerance of the organization, which is the degree of risk that the organization is willing to accept or avoid in pursuit of its objectives. Metrics based on risk tolerance can help to evaluate whether the information security program is aligned with the business strategy, supports the risk management process, and delivers value to the organization. Residual risk, regulatory requirements, and control objectives are also important factors to consider when developing metrics, but they are not as fundamental as the risk tolerance.
References = CISM Review Manual, 16th Edition, page 69