There are four generally accepted measurement bases or valuation principles: historical cost, fair value, net realizable value, and present value.

Historical Cost:
Historical cost is the original cost of an asset or liability when it was acquired or incurred. It represents the amount of money or the equivalent value exchanged at the time of the transaction. This measurement basis is widely used because it is objective and verifiable.

Fair Value:
Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. It is determined based on current market conditions and reflects the entity's expectations about the future cash flows associated with the asset or liability. Fair value is relevant when there is an active market for the asset or liability or when it can be estimated with reasonable accuracy.

Net Realizable Value:
Net realizable value is the estimated selling price of an asset less the estimated costs of completion, disposal, and transportation. It is used to measure the value of inventories and accounts receivable. This measurement basis is appropriate when the realizable value of an asset differs significantly from its historical cost.

Present Value:
Present value is the discounted value of future cash flows expected to be derived from an asset or liability. It takes into account the time value of money, which means that a dollar received in the future is worth less than a dollar received today. Present value is used to determine the value of long-term assets and liabilities, such as investments, loans, and pensions.

These four measurement bases or valuation principles are used in financial reporting to provide relevant and reliable information about an entity's assets, liabilities, and equity. The choice of measurement basis depends on the nature and characteristics of the item being measured, as well as the purpose of the financial statement users.