Population Size and Civil Conflict Risk: Is there a Causal Link?
利用干旱作为工具变量，研究1981-2004年37个撒哈拉以南非洲国家的人口规模增长是否导致国内冲突风险上升，发现人口增加5%使冲突风险提高约6个百分点。
Does an expansion of the population size expose nation states to a higher risk of suffering from civil conflict? Obtaining empirical evidence for a causal relationship is difficult due to reverse effects and omitted variable bias. This article addresses causality issues by using randomly occurring drought as an instrumental variable to generate exogenous variation in population size for a panel of 37 Sub-Saharan countries over the period 1981–2004. Instrumental variable estimates yield that a 5% increase in population size raises the risk of civil conflict by around six percentage points.