This page describes how every article on Japan in Data is researched, built, checked, and maintained. The same procedure applies to all articles regardless of topic, so that any figure on this site can be traced back to a primary source in the same way.
1. Which sources we use
We use primary sources only. In order of preference, these are:
- Official statistics of the Japanese government: e-Stat, the Statistics Bureau of Japan, and the statistical publications of individual ministries and agencies (for example the Ministry of Health, Labour and Welfare; the Ministry of Internal Affairs and Communications; the National Police Agency; the Japan Meteorological Agency; the Immigration Services Agency).
- Prefectural and municipal governments, for regional data not published nationally.
- International organizations: the OECD, the United Nations and its agencies, the World Bank, the IMF, the WHO, and the FAO.
- Official industry or professional bodies, only where no government statistic exists for the subject, and always named as such in the article.
News articles, commercial data aggregators, encyclopedias, and social media are not used as sources for figures. Where a figure can only be confirmed through such secondary reports, the fact-check section says so explicitly.
2. What we do not write
Japan in Data is an observation site. Every article is limited to describing what the data shows. We do not:
- attribute causes (“X happened because of Y”), unless the source itself states the cause and we quote it as the source’s statement;
- make predictions about future values;
- judge whether a figure is good, bad, high, or low, except relative to other figures in the same data;
- recommend what readers, companies, or governments should do.
Where a topic is widely discussed in terms of causes or policy, we may note that such discussion exists, but the article does not take a side.
3. How figures are produced
Every chart, map, and timeline is compiled and drawn by the Japan in Data editorial team from the source data cited beneath it. We do not republish charts from other publications. Charts are embedded as vector graphics so that they remain legible at any screen size and can be read by search engines and assistive technology.
Where we combine categories, convert units, or calculate a derived value (such as a rate per 1,000 people or a percentage change), the calculation is stated in the fact-check section and labeled as our own calculation. Values may differ slightly from the original publication because of rounding. Preliminary figures are labeled as preliminary and replaced when final figures are released.
4. The fact-check section
Every article ends with a fact-check section. Each key figure in the article is listed there with a link to the page where it can be verified, and one of four labels:
- Verified (primary): confirmed directly in an official or original publication.
- Confirmed (secondary): confirmed only through news reports or other secondary material; the primary document could not be reached.
- Our calculation: a value the editorial team calculated from primary data, with the formula stated.
- Subject to change: a figure that depends on conditions that change over time, such as an exchange rate or a preliminary count.
The fact-check section also lists the official information sources consulted for the article as a whole.
5. Updates
Each topic has one permanent URL. When the statistics behind an article are finalized, or when a new annual release is published, we update the existing article rather than publishing a new one. The date of the last update is shown at the top of each article. Older figures are replaced, not deleted from the time series, so that long-run charts stay complete.
6. Corrections
If a reader reports an error through the contact form, we check the point against the primary source. If the article is wrong, we correct it and add a dated correction note at the end of the article. Published figures are never changed silently.
7. Written for readers outside Japan
Japan in Data is an independent English-language site. Its topics and rules are shared with Kashikapedia (kashikapedia.com), the Japanese data-visualization site run by the same company, but each article is written for readers outside Japan: terms specific to Japan are defined where they first appear, and comparisons with other countries are added where official international data allows.
8. Responsibility
Japan in Data is published by the Japan in Data Editorial Team and operated by Nihon Kigyojoho Co., Ltd. (JCIB Co.), Tokyo, which is responsible for the content and accuracy of every article. Articles are written and narrated by Kaede Kobayashi, the site’s data editor (Grade 2 Financial Planning Technician and Certified Web Writing Professional, Japan; member of The Japan DataScientist Society), based in Saitama, Japan. Company details are listed on the About Us page.