Encouraging development  Using data from satellites measuring luminosity Michalopoulos and Papaioannou find that border areas with partitioned ethnic groups are up to 60% less developed than those towards the centre of countries so are not artificially split. Ethnicity is significant for trade. For example between Niger and Nigeria prices of millet increase at the border by 23.2% when it is also the border between ethnicities but only 9.3% when the same ethnicity is on both sides of the border for cowpea the figures are 20.2% and 14.4%. [1] Moreover internally where there is an ethnic border between markets there is a similar increase of 21% for millet and 22% for cowpea. [2] Ethnicity may also affect the ability to gain credit from other traders. [3] It therefore makes sense economically to have borders at ethnic boundaries due to the natural trading relations within an ethnic group. Splitting an ethnic group creates unnecessary hardship by making it more difficult to trade.  [1] Aker, 2010, p.16  [2] Ibid, p.21-2  [3] Ibid, p.25