What the sources report
BLS defines CPI around average price changes in a representative consumer basket. An index level and the percentage change in that index describe different quantities.
U.S. Bureau of Labor Statistics ↗The ECB explains that items receive different weights according to spending and that households have different consumption patterns. An average is not a personalized bill.
European Central Bank ↗The ONS guide uses percentage points for the difference between percentages. A change in a rate can also be expressed relative to the earlier rate, but that is a different calculation.
Office for National Statistics ↗What remains unclear
This explainer supplies no current inflation figure and makes no forecast about interest rates, wages or investment returns. Its fixed basket is deliberately simplified and does not reproduce the full CPI calculation. Real figures must be read with their release dates, coverage and methods. [24] [25]
How the story is being covered
BLS explains US consumer price measurement, the ECB explains inflation and spending weights in a euro-area context, and ONS explains how to compare percentages. These sources serve different purposes: they are not three independent measurements of current US inflation. US CPI and euro-area HICP are not interchangeable.
U.S. Bureau of Labor Statistics
primary ·Consumer Price Index Frequently Asked Questions ↗
Reporting focusUS consumer price measurement.
Framing & contextInstitutional guidance, not an independent test of outcomes.
Evidence group: U.S. Bureau of Labor Statistics. This identifies shared evidence, not editorial independence.European Central Bank
primary ·What is inflation? ↗
Reporting focusPrice levels, weighted baskets and euro-area context.
Framing & contextInstitutional guidance, not an independent test of outcomes.
Evidence group: European Central Bank. This identifies shared evidence, not editorial independence.Office for National Statistics
primary ·Percentages and percentage points ↗
Reporting focusPrecise language for comparing rates.
Framing & contextInstitutional guidance, not an independent test of outcomes.
Evidence group: Office for National Statistics. This identifies shared evidence, not editorial independence.Important context
Consider an invented, unchanged basket of purchases. It costs $100 at the start, $105 one year later and $107.10 after another year. The first annual increase is 5% ($5 divided by $100); the second is 2% ($2.10 divided by $105). Prices are still rising, but more slowly. These are hypothetical amounts, not reported CPI figures. [24] [25]
The basket costs 7.1% more after two years, not exactly 7% more. Multiply 1.05 by 1.02 to get 1.071: the second year's increase applies to the already higher bill. This simplified calculation illustrates compounding, not the full methodology of a consumer price index. [24]
The fall from 5% to 2% is 3 percentage points. It is also a 60% reduction in the rate, because 3 divided by 5 equals 0.60. Those statements describe the rate—not a 3% or 60% reduction in the basket's price. [26]
An average price index is not a personalized bill. Imagine one household spending heavily on rent and another spending more on commuting. Different category price changes can affect their budgets differently. BLS and the ECB explain why spending patterns matter; a mismatch with one household's experience does not by itself establish that the average is wrong. [24] [25]
When reading an inflation release, check the index name, geography, comparison period, published rate and what is being compared. Also check whether the figures are seasonally adjusted. A monthly change and a yearly change answer different questions. This is a suggested reading checklist, not an official statistical form. [24] [25]
Separate two questions: Did prices rise over the stated period? Did they rise more slowly than in the comparison period? In the hypothetical example, both answers are yes. For real figures, each answer needs support from the relevant release; a falling growth rate alone does not mean prices fell. [24] [25] [26]
Timeline
- The supplied source records date retrieval of the methodology and terminology pages to October 10, 2026. This is a research date, not the date of an inflation release or of the hypothetical basket changes. [24] [25] [26]
Sources & evidence
- Consumer Price Index Frequently Asked Questions ↗
U.S. Bureau of Labor Statistics · Retrieved 2026-10-10 21:16:43 UTC
- What is inflation? ↗
European Central Bank · Retrieved 2026-10-10 21:16:43 UTC
- Percentages and percentage points ↗
Office for National Statistics · Retrieved 2026-10-10 21:16:43 UTC
Updates & corrections
- Automated revision; separate Codex quality review passed. The worked example is hypothetical. Claims and source perspectives remain unchanged. This revision does not attest to completed human review or rights clearance.
- Initial unpublished draft. Source, rights, risk and separate quality reviews remain pending.