The price of oil has declined recently, but does that mean prices overall have declined? Let’s see if FRED can help us measure how much connection there is between oil prices and the general price level. The graph above compares oil price inflation and overall price inflation in the U.S. over recent decades. The red and blue lines plot the year-to-year inflation rate corresponding to two of the major aggregate price indexes: the producer price index (PPI) and the consumer price index (CPI). The green and purple lines plot the year-to-year percentage change in two of the major global oil price indexes: the price of Brent crude and the price of West Texas Intermediate (WTI) crude.

The graph shows a strong positive relationship between oil prices and PPI inflation: That is, higher oil prices are associated with higher producer prices and vice versa. Specifically, the correlation between oil prices and the PPI is 0.71. This strong link likely comes from the importance of oil as an input in the production of goods. In contrast, the graph shows a positive but much weaker relationship between oil prices and CPI inflation: The correlation is 0.27, much lower than for producer prices. This weaker link between oil prices and consumer prices likely comes from the relatively higher weight of services in the U.S. consumption basket, which you’d expect to rely less on oil as a production input. If you know what to look for, this difference in correlation is more clearly visible in the scatter plot below: The red dots (PPI and oil) more or less follow a 45-degree line that rises from left to right, which translates into a strong positive relationship between PPI and oil prices. The stream of blue dots (CPI and oil) doesn’t strictly follow a 45-degree line, which reveals a much weaker relationship.

How these graphs were created: Search for “CPI” and click on the series name. From the “Edit Graph” panel, open the “Add Line” tab and search for “PPI,” then click on the series name. Repeat this procedure searching for “oil price” to add the remaining series. From the “Format” tab: Set the “y-axis” position corresponding to the oil price series to “right,” set the “Graph frame” color to white, and set the thickness of each of the lines to 3. For the second graph, from the “Format” tab, change the graph type to “Scatter.”

Suggested by Fernando Leibovici.