There is a correlation between poverty and civil war, but the causality (which causes the other) is unclear. Some studies have found that in regions with lower income per capita, the likelihood of civil war is greater. Economists Simeon Djankov and Marta Reynal-Querol argue that the correlation is spurious, and that lower income and heightened conflict are instead products of other phenomena. In contrast, a study by Alex Braithwaite and colleagues showed systematic evidence of "a causal arrow running from poverty to conflict".