Draper Company's controller explained to the company's president, Dana Draper, that if the inventory's value should decrease below its original cost, the inventory must be written down, and a loss must be recognized. The controller told the president that this is called the lower of cost or market rule. The president was unclear as to the purpose of this rule and wanted to know the disadvantages of this method. Required:

a. State the accounting convention that supports the lower of cost or market rule, and in this context, discuss the purpose of the rule.

b. Discuss the criticisms of the lower of cost or market rule in the valuation of inventories.