To date the focus of measurement in standard setting has been on individual assets and liabilities, and the lack of concepts for these measurements is obvious. However, aggregate amounts are also fundamental to financial reporting---financial reports include key aggregate amounts such as total assets, total liabilities, and net income. Changes in measurements of assets and liabilities during the reporting period also are fundamental because they determine items of income and expense, as well as comprehensive income itself. Thus, if financial reports are to achieve their objective, measurement concepts need to deal with aggregate amounts and changes in measurements, as well as the implications of the measurements for the information revealed in a set of financial statements taken together.