Reading the indicators: the five measures in the Bank of Japan core price indicatorsFive measuring sticks for the real strength of price rises
On October 27 the Bank of Japan posted the latest data for its core indicators of the consumer price index. Based on the consumer price index published by the Ministry of Internal Affairs and Communications, it produces consumer prices excluding special factors, together with the trimmed mean, the weighted median, the mode and the ratio of rising and falling items, which use the distribution of price changes across items. This article sets out how each one is built.
Key points
- Five indicators are posted: consumer prices excluding special factors, the trimmed mean, the weighted median, the mode, and the ratio of rising and falling items
- Consumer prices excluding special factors removes the effects of changes in the consumption tax rate, free education policies, mobile phone charges, travel support, and the measures easing the cost of petrol, electricity and gas
- The trimmed mean, the weighted median, the mode and the ratio of rising and falling items are calculated using the distribution of price changes across items
- Publication is in principle targeted for 14:00 two business days after the publication of the nationwide consumer price index. The latest data were posted on October 27, 2026
What to do in practice
- Read the consumer price index published by the Ministry of Internal Affairs and Communications (the all-items index, the index excluding fresh food, and so on) separately from the Bank of Japan core indicators
- When you want to see price movements with the effects of government relief measures removed, check the index excluding special factors
When you look at how fast prices are rising, changing the way you count changes what you can see. On October 27 the Bank of Japan published, separately from the ordinary price figures, numbers that leave out special circumstances and numbers calculated from how the price changes of individual goods are spread out. There are five measuring sticks in all.
- ○Applies: Consumer prices with special circumstances left out
- ○Applies: Trimmed mean
- ○Applies: Weighted median
- ○Applies: Mode
- ○Applies: Share of goods that rose and fell
Points
- The first leaves out special circumstances, such as a change in the consumption tax or government measures to hold down the cost of petrol, electricity and gas
- The other four are calculated from how the price changes of individual goods are spread out: the trimmed mean, the weighted median, the mode, and the share of goods that rose and fell
- These are made by the Bank of Japan, separately from the ordinary price figures published by the Ministry of Internal Affairs and Communications
What the words mean
- Consumer prices
- A figure that gathers together the prices of what households buy
- Distribution
- How the numbers are spread out
- Underlying trend
- The everyday flow, with temporary movements left out
- Bank of Japan: Bank of Japan, Core indicators of the consumer price index
Economic news presents published statistics and outlooks. It is not investment solicitation or trading advice. Figures are as of publication and may be revised.
This article summarizes and explains materials published by government agencies and is not advice on any individual case. Rules can change, so for actual procedures and decisions always check the latest original materials and consult professionals such as tax accountants or labor and social security attorneys. English, Simplified Chinese and Traditional Chinese versions are translations prepared from the Japanese articles for convenience. If anything differs, the Japanese text and the original source take precedence.