Why don't you include information on minimum and maximum temperature extremes?
The Factbook staff judges that this information would only be useful for some (generally smaller) countries. Larger countries can have large temperature extremes that do not represent the landmass as a whole. In the future, such a category may be adopted listing the extremes, but also adding a normal temperature range found throughout most of a country's territory.
What information sources are used for the country flags?
Flag designs used in The World Factbook are those recognized by the protocol office of the US Department of State.
Why do your GDP (Gross Domestic Product) statistics differ from other sources?
We have two sets of GDP dollar estimates in The World Factbook , one derived from purchasing power parity (PPP) calculations and the other derived using official exchange rates (OER). Other sources probably use one of the two. See the Notes and Definitions section on GDP and GDP methodology for more information.
On the CIA Web site, Chiefs of State is updated weekly, but the last update for the Factbook was an earlier date. Why the discrepancy?
Although Chiefs of State and The World Factbook both appear on the CIA Web site, they are produced and updated by separate staffs. Chiefs of State includes fewer countries but more leaders, and is updated more frequently than The World Factbook, which has a much larger database, and includes all countries.
Some percentage distributions do not add to 100. Why not?
Because of rounding, percentage distributions do not always add precisely to 100%. Rounding of numbers always results in a loss of precision—i.e., error. This error becomes apparent when percentage data are totaled, as the following two examples show: