Definition
Single Loss Expectancy (SLE) represents the estimated monetary loss a single occurrence of a specific threat would cause to an organization. It is calculated by multiplying the asset's value by its exposure factor, which is the percentage of the asset's value that would be lost if the threat were realized. Understanding SLE is crucial for prioritizing security investments and making informed risk management decisions. For instance, if a server worth $10,000 has an exposure factor of 50%, its SLE is $5,000, meaning a successful attack could cost $5,000 in direct losses. SLE differs from Annualized Loss Expectancy (ALE) by focusing on a single event rather than an annual average. This metric is commonly found in cybersecurity certifications like CompTIA Security+ and CISSP.