Inflation has been high recently, not just in the US but in many parts of the world. How inflation is calculated is to take a basket of goods and calculate their cost and see how they change over time. In the US, there are two inflation indices: regular inflation and what is called ‘core inflation’, which omits food and fuel from the basket because those tend to fluctuate more over the short term and thus introduces volatility.
Whichever index you choose, whenever the inflation figures are reported each month in the US, Kevin Drum complains about the fact that it is the year-over-year number that is reported. He says that this gives a misleading picture of whether there is inflation right now and that a month-to-month comparison would be better.