Because accounting information is needed for purposes of economic evaluation and decision-making, I suggested that financial statements should incorporate current value data which can assist in these tasks. The first and main requirement is that all items in the income statement for a particular period, and in the balance sheet at the end of the period, should be valued in terms of current prices of the period. In my current valuation system, I interpret current prices as pertaining to particular goods and services which are recorded in the financial statements in question, and not the prices of a hypothetical collection of goods and services which are valued by reference to a general purchasing power index. My income concept is restricted to the increment in wealth resulting from productive activities as represented by actual transactions, with both revenue and cost flows expressed in current prices. Income is not derived by reference to the change in balance sheet measures of generalized purchasing power between two points of time. Such measures are fictional representations of wealth, and have little relevance to the individual firm that has used its purchasing power to buy specific assets. In my system, wealth may change as a result of factors other than income flows associated with the productive activities of the enterprise, for example capital gains or losses, specific price changes or general price changes. But these, like capital contributions and withdrawals, are treated by me as capital adjustments or restatements of wealth and not as elements of income.