Knowing the likelihood of a threat exploiting a vulnerability directly informs the probability of a security incident. It provides a measure of how often a threat could succeed, given the opportunity, which is essential for risk assessment in order to prioritize actions and resource allocation. Historical data and trend analysis could also support this assessment by looking at past occurrences, but they are secondary to understanding the current likelihood. Vendor-provided statistics and geographic location data might have some impact on probability; however, without the specific context of likelihood, they provide less direct information for assessing the probability of an incident.