ISCED level 0 programmes are usually school-based or otherwise institutionalised for a group of children (e.g. centre-based, community-based, home-based). ISCED level 0 excludes purely family-based arrangements that may be purposeful but are not organized in a ‘programme’ (e.g. informal learning by children from their parents, other relatives or friends is not included under ISCED 0).
Within ISCED 0, early childhood educational development programmes are targeted at children aged 0 to 2 years; and pre-primary education programmes are targeted at children aged 3 years until the age to start ISCED 1. The upper age limit for the pre-primary education category depends in each case on the theoretical age of entry into ISCED level 1. (See ISCED 2011 Manual, paragraphs 107-108)
ISCED 2011
http://uis.unesco.org/sites/default/files/documents/international-standa...