David Keen, a professor at the Development Studies Institute at the London School of Economics is one of the major critics of greed vs. grievance theory, defined primarily by Paul Collier, and argues the point that a conflict, although he cannot define it, cannot be pinpointed to simply one motive. He believes that conflicts are much more complex and thus should not be analyzed through simplified methods. He disagrees with the quantitative research methods of Collier and believes a stronger emphasis should be put on personal data and human perspective of the people in conflict.