Release of Research Data "Indicators for Core CPI"

March 26, 2026
Research and Statistics Department
Bank of Japan

The Bank of Japan's Research and Statistics Department has begun publishing data on the estimated consumer price inflation (CPI) rate, which excludes institutional factors, to accurately capture developments in prices. It will be published monthly on the "Indicators for Core CPI" page of the Bank's website, alongside various indices previously released as "Measures of Underlying Inflation." The published data are as follows.

(i) CPI that excludes "institutional factors"
(ii) trimmed mean
(iii) weighted median
(iv) mode
(v) diffusion index of increasing/decreasing items

-- Data for (i) exclude the effects of institutional factors from official data released by the Ministry of Internal Affairs and Communications. These institutional factors include: (1) changes in the consumption tax rate; (2) policies concerning the provision of free education; (3) the reduction in mobile phone charges in 2021; (4) travel subsidy programs; and (5) measures to reduce the energy cost burden (such as gasoline prices, electricity and gas charges). Effects of institutional factors are staff estimates by the Bank of Japan's Research and Statistics Department.
Three types of series [all items less fresh food; all items less fresh food and energy; all items less food and energy] will be published. Please note that the definition of institutional factors may be subject to change without prior notice.

Data for (ii) to (v) are the same indicators that have been published under "Measures of Underlying Inflation." For further details, please see the Bank of Japan Review Series below.

Data are, in principle, released at 2:00 p.m., two business days after the release of the official CPI for Japan.

Inquiries

Economic Assessment and Projection Group,
Economic Research Division, Research and Statistics Department

Tel : +81-3-3279-1111