Senator Wong: The answer to the honourable senator's question is as follows: The Australian Bureau of Statistics (ABS) has advised that "purchasing power" is the ability of households to acquire goods and services. There are two main determinants of the purchasing power of a household: the prices of goods and services—these determine the quantity of goods and services which can be acquired with a given amount of money the amount of money available to the household to acquire goods and services—the main sources of this are household income and wealth (net worth). The CPI measures price change facing households. Indexing the income of the household by the CPI allows the household to maintain its acquisition of goods and services at the same level over time.