The Fed closely watches a cumbersome-sounding index, the core personal consumption expenditure deflator, for signs of inflation, and in the last few months, that indicator has dropped within the range Bernanke has been looking for--after three years of coming in above his range.

FORBES: Magazine Article

Inflation, as measured by the core personal-consumption-expenditure deflator (excluding food and energy) fell to 0.7% at an annual rate in the third quarter, its lowest since 1962.

ECONOMIST: Overview