The APB originally studied this problem and issued its findings in APB Opinion No.20, “Accounting Changes” (superseded). This release identified three types of accounting changes, discussed the general question of errors in the preparation of financial statements, and defined these changes and errors as follows.
1. Change in an accounting principle. This type of change occurs when an entity adopts a GAAP that differs from one previously used for reporting purposes. Examples of such changes are a changes are a change from LIFO to FIFO inventory pricing or a change in depreciation methods.
2. Change in an accounting estimate. These changes result from the necessary consequences of periodic presentation. That is, financial statement presentation requires estimation of future events, and such estimates are subject to periodic review. Examples of such changes are the life of depreciable assets and the estimated collectability of receivables.
3. Change in a reporting entity. Changes of this type are caused by changes in reporting units, which may be the result of consolidations, changes in specific subsidiaries, or a change in the number of companies consolidated.
4. Errors. Errors are not viewed as accounting changes; rather, they are the result of mistakes or oversights such as the use of incorrect accounting methods or mathematical miscalculations.
The Board then specified the accounting treatment required to satisfy disclosure requirements of APB Opinion No. 20