Data sources and methodology
ranki.gg does not invent a number. If a figure is not in a cited source, it is not on a card.
Every puzzle stores a source line, a URL, a year when the publisher has one, and a short fact. The fact is allowed to explain a contrast that the same source supports. It is not allowed to smuggle in a second, unsourced statistic. Where a measure is easy to misread, the fact or the caveat says so in plain words. Food-supply figures are kilograms available for consumption, not a weighed dinner. A renewable-energy share can be firewood. A time-zone count includes territories and leaves out daylight saving. An English-speaker count is people who say they speak English, and the census years differ.
Publishers used on the learn pages
- Our World in Data and the UN FAO. Rice, potatoes, and onions use FAO food balances as published by Our World in Data: food available for consumption, kilograms per person per year.
- FAOSTAT. Garlic is item 406, production plus imports minus exports, divided by population, for 2023, computed from FAOSTAT and labeled as supply, not food eaten. Tea (including mate), coffee and products, and cocoa beans and products are Food Balance Sheet food-supply quantities for 2023, in kilograms per person. FAO marks those 2023 supply rows as estimated. Tea includes yerba mate. Coffee is in primary equivalent. China in those three series is the mainland row, so Hong Kong and Taiwan stay separate.
- World Bank and UN DESA. Life expectancy at birth is SP.DYN.LE00.IN for 2024, from the UN Population Division, which is the population division of UN DESA. Forest area as a share of land is the FAO Global Forest Resources Assessment via the World Bank. Renewable energy as a share of final energy is the World Bank SDG 7.2 series for 2021, drawing on the IEA, IRENA, the UN Statistics Division, the WHO, and the World Bank. Population for the one-time-zone card is SP.POP.TOTL for 2024. Hours worked come from the Penn World Table via Our World in Data.
- UNDP. The Human Development Index on the quality-of-life card is the Human Development Report 2025 figure for 2023, on a 0 to 1 scale.
- World Inequality Database (WID.world). A Top 1 card uses the wealth share of the richest 1 percent, published by WID via Our World in Data. That card is not written up on the learn pages. The figure on it is a share of wealth, not income per person.
- Ethnologue, via the Wikipedia list the puzzle cites. Total speakers are native plus second language, 29th edition.
- Wikipedia tables the puzzles name. Time zones are the list of time zones by country: standard UTC offsets, territories included, Antarctic claims excluded, daylight saving not an extra zone. English speakers are that list's total column. The quiz cards each link their own article, from Emojipedia to the Cambridge coffee-pot timeline.
- BBC Future, 3 September 2021. The finger-counting card uses only the country methods that article describes.
- Glottolog, plus the alphabet notes the language-family fact cites. Indo-European, Uralic, Turkic, and Mongolic are the four tiers on that card.
- UNODC and WHO. Some later dailies use international crime statistics from UNODC and health statistics from the World Health Organization. Those topics are not written up on the learn pages. The game keeps them off the AdSense-safe dates.
What a card is allowed to do
A Rank it shows the values and asks you to match countries to them. A Tier it asks which countries share a label. A multiple-choice question has four countries and one answer, then the fact. Guess the number shows one real value and asks for another. Top 1 asks which country is first in a longer list. The weight of a part in the daily bundle is separate from how accurate your guess was. The learn pages do not score you. They only show the table and the fact.
Spotted a copied figure that does not match the linked source? Write to mikelyaps@gmail.com with the puzzle name, the country, and the URL. That address is the contact address stored for the site. Corrections are how the tables stay tied to the publisher.