The probability of stocking out is the likelihood that the demand for an item will exceed the available inventory during a given period. It is one of the criteria used to determine safety stock in a distribution center (DC), as safety stock is inventory that is carried to protect against forecast errors and fluctuations in demand or supply. The higher the probability of stocking out, the more safety stock is needed to avoid customer dissatisfaction and lost sales. The other criteria are not directly related to safety stock. Economic order quantity (EOQ) is the order quantity that minimizes the total inventory holding and ordering costs. Seasonal index value is a measure of how demand varies according to different seasons or periods. Alpha factor level is a parameter used in exponential smoothing to adjust the forecast based on the error between the actual and forecasted demand. References: Safety Stock: A Contingency Plan to Keep Supply Chains Flying High, APICS CPIM 8 Planning and Inventory Management | ASCM