* Definition of "school": The definition varies widely. Does it include preschools, primary schools, secondary schools, universities, vocational schools, and other types of educational institutions? Different countries and organizations use different classifications.
* Data collection challenges: Many countries, particularly developing nations, lack comprehensive and regularly updated educational statistics. Data collection is often inconsistent and unreliable.
* Accessibility of data: Even when data exists, it may not be publicly accessible or easily compiled.
Therefore, while various organizations attempt to estimate the global number of schools, the figures are always approximations and should be treated with caution. You'll find a wide range of estimates depending on the source and methodology used.