The first being weighted average costs which assumes that all costs, whether accumulated in a previous period or in the current period, are grouped together and allocated to the units produced. The weighted average method is commonly used in cases where there is no standard costing system. The second is the FIFO method which means “first in, first out”. FIFO costing is used when there are significant changes in product costs from each period. When this happens, management must be aware of the new cost levels so they can re-evaluate products appropriately, determine if there are problems with internal costs that require a solution or if there is a need to change performance of the manager based on performance.