State-Dependent or Time-Dependent Pricing: Does It Matter for Recent U.S. Inflation? *

In the 1988–2004 microdata collected by the U.S. Bureau of Labor Statistics for the Consumer Price Index, price changes are frequent (every 4–7 months, depending on the treatment of sale prices) and large in absolute value (on the order of 10%). The size and timing of price changes vary considerably for a given item, but the size and probability of a price change are unrelated to the time since the last price change. Movements in aggregate inflation reflect movements in the size of price changes rather than the fraction of items changing price, because of offsetting movements in the fraction of price increases and decreases. Neither leading time-dependent models (Taylor or Calvo) nor first-generation…