Which type of indicators should be developed to measure the effectiveness of an organization '...

The best type of indicators to measure the effectiveness of an organization’s firewall rule set are key control indicators (KCIs). A firewall is a device or software that filters the network traffic based on a set of rules or policies. A firewall rule set is the configuration of the firewall that defines the criteria for allowing or blocking the traffic. A key control indicator is a metric that measures the performance and effectiveness of a control in achieving its objectives and mitigating the risks. A key control indicator can help to evaluate the adequacy and efficiency of the firewall rule set, and to identify any gaps, weaknesses, or issues that need to be addressed.Key risk indicators (KRIs), key management indicators (KMIs), and key performance indicators (KPIs) are not as suitable as key control indicators, as they measure different aspects of the risk management process, such as the level and nature of the risk exposure, the alignment and integration of the risk management activities, and the achievement of the risk management goals and targets. References = CRISC Review Manual, 6th Edition, ISACA, 2015, page 220.