The best indicator of an effective IT security awareness program is the decreased success rate of internal phishing tests. Phishing is a type of social engineering attack that attempts to trick the users into revealing their personal or confidential information, or clicking on malicious links or attachments, by impersonating a legitimate entity or person. Internal phishing tests are simulated phishing attacks that are conducted by the enterprise to test the awareness and behavior of the employees in response to phishing emails. A decreased success rate of internal phishing tests means that fewer employees fall victim to the phishing attempts, and that they are more aware and vigilant of the phishing threats and techniques. A decreased success rate of internal phishing tests also implies that the IT security awareness program has effectively educated and trained the employees on how to recognize and report phishing emails, and how to protect themselves and the enterprise from phishing attacks. A decreased number of reported security incidents, a number of disciplinary actions issued for security violations, and a number of employees that complete security training are not as good indicators of an effective IT security awareness program as a decreased success rate of internal phishing tests, as they do not directly measure theawareness and behavior of the employees in relation to phishing, and may be influenced by otherfactors such as reporting mechanisms, enforcement policies, and training availability. References = CRISC Review Manual, 6th Edition, ISACA, 2015, page 220.