Equivalent units in beginning inventory. To assign some cost to spoilage, the number of equivalent units for each element of cost in the spoiled units must be determined and added to the denominator before the cost per equivalent unit is computed. This approach assigns only current period cost to spoilage. Although some of the spoiled units actually may have been among those that were in beginning inventory, which technically should be assigned some cost from the prior period , only cost added during the current period is typically assigned goods. This simplification is acceptable if it is applied consistently each period and if the difference in cost is immaterial. The treatment of spoilage in the average method is illustrated in the appendix to this chapter.