12. The first-in, first-out method approximates the specific identification method when the physical flow
of goods is on a FIFO basis. When the goods are subject to spoilage or deterioration, FIFO is
particularly appropriate. In comparison to the specific identification method, an attractive aspect of
FIFO is the elimination of the danger of artificial determination of income by the selection of
advantageously priced items to be sold. The basic assumption is that costs should be charged in
The results achieved by the average-cost method resemble those of the specific identification
method where items are chosen at random or there is a rapid inventory turnover. Compared with
the specific identification method, the average-cost method has the advantage that the goods
need not be individually identified; therefore accounting is not so costly and the method can be
applied to fungible goods. The average-cost method is also appropriate when there is no marked
trend in price changes. In opposition, it is argued that the method is illogical. Since it assumes that
all sales are made proportionally from all purchases and that inventories will always include units
from the first purchases, it is argued that the method is illogical because it is contrary to the
chronological flow of goods. In addition, in periods of price changes there is a lag between current
costs and costs assigned to income or to the valuation of inventories.
13. A company may obtain a price index from an outside source (external index)—the government, a
trade association, an exchange—or by computing its own index (internal index) using the double