Alternative price indexes Because there isn't one single measure of inflation, the government and researchers use a variety of methods to get the most balanced picture of how prices fluctuate in the economy. Two of the most commonly used price indexes are the consumer price index (CPI) and the GDP deflator. The GDP deflator for this year is calculated by dividing theusing theby the using the by mulyiplying by 100.However the GDP deflator reflects only the prices of all goods and services