The Fed's preferred inflation gauges are deflators of Personal Consumption Expenditures (PCE), the consumer spending component of GDP. These price indices are based on a few input data sources, including the Consumer Price Indices (CPI),Producer Price Indices (PPI), and Import Price Index (IPI), but are methodologically distinct from them. We usually have a decent read of PCE deflators after CPI (which tends to be the first inflation gauge released), but there are a lot of controls and calculations to account for. When updating views month to month about inflation, the dirty work here matters.