historical cost is always a relevant measure of an asset
Historical cost In accounting under the traditional historical cost paradigm, historical cost is the original nominal monetary value of an economic item.[1] Historical cost is based on the stable measuring unit assumption. In some circumstances, assets and liabilities may be shown at their historical cost, as if there had been no change in value since the date of acquisition. The balance sheet value of the item may therefore differ from the real value.
Accounting rate of return Accounting rate of return, also known as the Average rate of return, or ARR is a financial ratio used in capital budgeting.[1] The ratio does not take into account the concept of time value of money. ARR calculates the return, generated from net income of the proposed capital investment. The ARR is a percentage return. Say, if ARR = 7%, then it means that the project is expected to earn seven cents out of each dollar invested (yearly). If the ARR is equal to or greater than the required rate of return, the project is acceptable. If it is less than the desired rate, it should be rejected. When comparing investments, the higher the ARR, the more attractive the investment. More than half of large firms calculate ARR when appraising projects.[2]