For decades, economists and central bankers have relied more on the Core Consumer Price Index (CPI) than the headline CPI because Core CPI excludes volatile food and energy prices; this permits a clearer read on long-term inflation trends, which is critical for setting interest rates and guiding economic policy.
Think of it like steering a ship: if you focus only on the choppy surface waves (headline inflation), you’ll get tossed around by every sudden storm in food or energy markets. Core CPI lets you read the underlying current and where the economy is truly headed.
The Data Tell the Story
- June 2025 Core CPI: Up 2.9 percent year-over-year (from 2.8 percent in May), slightly below the 3 percent economists expected. Headline CPI was 2.7 percent.
- July 2025 Core CPI: Rose to 3.1 percent year-over-year, above forecasts. Headline CPI stayed at 2.7 percent.
- Month-over-month July Core CPI: Up 0.3 percent — an annualized pace of 3.6 percent, accelerating from May’s 1.2 percent and June’s 2.4 percent.
Economists noticed the climb began in May, and the timing coincides with the start of President Trump’s new tariffs, which many expect will raise prices on imported goods, by year end. July’s data showed increases in tariff-sensitive categories: household furnishings, appliances, toys, and footwear (apparel was the exception).
The New York Post headline on August 12 summarized this belief: “Inflation came in flat in July – the Core figure rises in sign that Trump’s tariffs are hitting prices.”
What’s Driving It
From the July report, certain categories posted price gains well above the Fed’s two-percent target:
- Used autos: +4.8 percent
- Medical services: +4.3 percent
- Housing: +3.7 percent
- Transportation: +3.5 percent
- Food: +2.9 percent
Energy was the outlier, falling 1.6 percent, which helped hold headline CPI steady.
The report arrived amid ongoing trade developments that could further alter the US effective tariff rate, now hovering near 18.6 percent — the highest since 1933, according to the latest Yale Budget Lab estimate.
Behind the numbers are trade realities often overlooked:
- In 2024, 15 countries accounted for 75 percent of US trade. Mexico (1), Canada (2), China (3), India (10), and Brazil (15) alone represented 45.1 percent.
- To date, negotiations with China, Mexico, Canada, India, and Brazil remain unsettled.
- To many Americans’ surprise, the US imports 97–99 percent of footwear, over 60 percent of appliances, and over 50 percent of furniture.
- Canada supplies 30 percent of our softwood lumber, 90 percent of potash, 25 percent of nitrogen fertilizer, and 62 percent of crude oil imports — vital for the operation of Midwest refineries designed for heavy oil.
When tariffs hit such concentrated supply chains, price effects can spread fast.
Why CPI Alone Isn’t the Whole Picture
Two days after the July CPI report, the Producer Price Index (PPI) landed and initially shocked Wall Street. Like CPI, PPI has headline and core measures, but it tracks wholesale prices for producers. Many economists view PPI as a forewarning for consumer prices, as businesses often pass higher input costs on to consumers.
After flat readings in June, July’s numbers jumped:
- Headline PPI: Up 3.3 percent year-over-year (vs. 2.5 percent expected) and 0.9 percent month-over-month, the largest in over three years. Annualized, that’s about 11 percent.
- Core PPI: Up 3.7 percent year-over-year (vs. 2.9 percent expected) and also +0.9 percent month-over-month, also a more-than-three-year high. A more detailed breakdown showed machinery and equipment at the wholesale level jumped 3.8 percent, with fresh and dry vegetables rising 38.9 percent. This sharp move suggests tariff costs are filtering through the production pipeline, potentially altering future CPI data.
Going Deeper on the Core CPI
As noted earlier, the Core CPI has long been the preferred tool for economists, central bankers, and many financial market analysts. Here’s why it holds such weight in shaping economic policy and market expectations.
1. Reduced Volatility
Food and energy prices are notoriously unpredictable. A bad harvest in the Midwest, an early frost in Brazil’s coffee fields, or a geopolitical flare-up in the Middle East can send prices soaring or plunging overnight. Energy markets are particularly vulnerable to disruptions in oil production, refinery capacity, and transportation routes. While these swings matter to consumers, they often represent short-term shocks rather than lasting changes in aggregate price structure. By removing food and energy, Core CPI filters out “noise” from erratic changes. The result is a smoother, more stable metric that better reflects the general trend in consumer prices.
2. Clearer Long-Term Trend
Headline CPI can be skewed by seasonal factors or one-off events. For example, a hurricane that disrupts Gulf Coast oil production might cause a sharp increase in gasoline prices for a month or two — but that doesn’t necessarily mean the entire economy is overheating. Core CPI removes such anomalies, providing a clearer picture of the “fundamental” inflation rate. For economists, this clarity is invaluable. It helps determine whether inflationary pressures are building up across a broad range of goods and services or if it’s just the effects of a single, temporary disruption. This distinction is critical for avoiding overreaction — or underreaction — in policy decisions.
3. Better Policy Guidance
Monetary policy works on a lag. When the Federal Reserve adjusts interest rates, it can take months to fully ripple through the economy. Core CPI’s steadier readings make it easier to set policy with confidence. If the Fed relied solely on headline CPI, it could be misled into changing policy in response to short-lived events. By focusing on Core CPI, policymakers can avoid chasing every wave and instead steer toward long-term stability — helping preserve economic growth while keeping inflation in check.
The Bottom Line
Core CPI and Core PPI are flashing warning signs: prices are heating up in key areas. Business leaders should watch the August reports closely and be ready to adjust strategies if the trend continues.
At the same time, the broader US economy remains caught between unexpected strength and surprising weakness: productivity gains from AI are fueling growth, while an underperforming housing market is an economic laggard. How policymakers balance these opposing forces will shape the inflation path through year-end. If One Big Beautiful Bill (OBBB) should spurs promised economic growth by Q4 and into 2026, that could mitigate future tariff concerns.
The post Core vs Headline: What Really Drives Inflation Calculations was first published by the American Institute for Economic Research (AIER), and is republished here with permission. Please support their efforts.