Why can the list of sub-Saharan African countries vary among organizations?

The list of countries categorized as sub-Saharan Africa can vary between organizations because the classification often depends on the specific purpose of the categorization and the criteria used by the compiling entity.1

While the region is generally defined as the area of Africa lying south of the Sahara, the inclusion of certain nations can be subjective. For example, some organizations may group countries like Sudan with North Africa rather than sub-Saharan Africa, depending on their geopolitical or regional focus.1