Lower of Cost or Net Realizable Value Method. The lower of cost or net realizable value (NRV) method is often referred to as a one-way street because ending inventory values may be written down to a lower NRV but are never written up when the expected NRV exceeds the inventory cost basis. What accounting principle is reflected in the application of the method? What accounting principle is violated by its applica- tion? Discuss whether you think that lower of cost or NRV should be modified to become a two-way street, allowing both inventory value write-ups and write-downs.