Replication Data for: "Leadership and Military Effectiveness"

What are the sources of military effectiveness? Though for decades political scientists have studied the determinants of military effectiveness, they have generally ignored the role of military leadership, a factor that military historians and other observers have emphasized for millennia as crucial for effectiveness. This paper presents the first rigorous examination of the notion that militaries improve effectiveness by replacing low-performing leaders. The paper first presents theory as to why leadership contributes to military effectiveness. It then presents a theory describing how during wartime militaries replace low-performing leaders. It next presents hypotheses describing conditions under which low-performing leaders might not get replaced, if those leaders belong to powerful interpersonal networks, or if civilian dictators keep low-performers in place because those officers are politically loyal. Hypotheses are tested using new data on all American and German generals holding combat commands in the North African, Italian, and West European theaters in World War II, and new data on the monthly combat performance of all American and German divisions fighting in these theaters. Event history and regression analysis reveal that both armies improved effectiveness by replacing low-performing generals, and that neither interpersonal networks nor dictatorial political preferences disrupted this dynamic.