Consumer prices excluding food and energy, as a percentage change over twelve months. It is the inflation measure the Federal Reserve watches most for persistence.
Threshold source: Federal Reserve target of 2 % on PCE; 3.5 % on CPI is the level at which policy has historically stayed restrictive. How thresholds are chosen
Shelter is a third of the index and lags market rents by a year, so core CPI overstates inflation late in a disinflation and understates it early in one.