What We Know About Leadership Robert Hogan Hogan Assessment Systems Robert B. Kaiser Kaplan DeVries Inc. This article reviews the empirical literature on personality, leadership, and organiza- tional effectiveness to make 3 major points. First, leadership is a real and vastly consequential phenomenon, perhaps the single most important issue in the human sciences. Second, leadership is about the performance of teams, groups, and organiza- tions. Good leadership promotes effective team and group performance, which in turn enhances the well-being of the incumbents; bad leadership degrades the quality of life for everyone associated with it. Third, personality predicts leadership—who we are is how we lead—and this information can be used to select future leaders or improve the performance of current incumbents. A very smart political scientist friend used to say, “The fundamental question in human af- fairs is, who shall rule?” We think the funda- mental question is, “who should rule?” Leader- ship is one of the most important topics in the human sciences and historically one of the more poorly understood; it is important for two rea- sons. First, leadership solves the problem of how to organize collective effort; consequently, it is the key to organizational effectiveness. With good leadership, organizations (govern- ments, corporations, universities, hospitals, armies) thrive and prosper. When organizations succeed, the financial and psychological well- being of the incumbents is enhanced. Second, and more important from a moral perspective, bad leaders perpetrate terrible mis- ery on those subject to their domain. Consider the career of Foday Sankoh, the former dictator of Sierra Leone, who died in July 2003. Sankoh was born in 1937 and grew up in a Sierra Leone dominated by a small, corrupt urban elite whom he deeply resented. He joined the Sierra Leo- nean army but was sent to prison for 7 years in 1971 for taking part in an attempted coup. After his release, he went to Libya to train with other West African revolutionaries; there he met Charles Taylor (the recently deposed dictator of Liberia), who became Sankoh’s major ally. Sankoh founded the Revolutionary United Front to overthrow the Sierra Leonean govern- ment and take over the country’s diamond mines. Sankoh was bright, charming, and charis- matic, and he immediately attracted a large pop- ular following, especially among the teenage underclass. He promised to reform education, health care, and other public services and to distribute the diamond revenues. Instead, he used the revenues to buy arms (from Charles Taylor) and political support. He paid his sol- diers irregularly because he expected them to live by looting and even by cannibalizing vic- tims of the army. New recruits were sometimes required to murder their own parents, which toughened them and made it hard to return home. His young recruits, deprived of parenting and raised in chaos, were notoriously savage and specialized in amputating appendages, which they kept in bags. Those with the most body parts were rewarded. By the end of the 1990s, Sierra Leone was, according to the United Nations, the poorest country on earth. To stop the slaughter and ameliorate the misery, the United Nations, after several false starts, inter- vened in 2000. Sankoh was taken captive by an emboldened mob that had been fired upon by his bodyguards. He was subsequently indicted Robert Hogan, Hogan Assessment Systems, Tulsa, Okla- homa; Robert B. Kaiser, Kaplan DeVries Inc., Greensboro, North Carolina. We are grateful for the helpful comments of Roy Baumeister and John Antonakis on earlier versions of this article. Correspondence concerning this article should be ad- dressed to Robert Hogan, Hogan Assessment Systems, 2622 East 21st Street, Tulsa, OK 74114, or Robert B. Kaiser, Kaplan DeVries Inc., 1903 G Ashwood Court, Greensboro, NC 27455. E-mail: rhogan@hoganassessments.com or rkaiser@kaplandevries.com Review of General Psychology Copyright 2005 by the Educational Publishing Foundation 2005, Vol. 9, No. 2, 169 –180 1089-2680/05/$12.00 DOI: 10.1037/1089-2680.9.2.169 169