Shiping Tang, Yihan Xiong, and Hui Li’s recent article, “Does Oil Cause Ethnic War? Comparing Evidence from Process-Tracing with Quantitative Results,” is a companion piece to another article, by Hui and Tang, published in the Chinese Political Science Review: “Location, Location, and Location: The Ethno-Geography of Oil and the Onset of Civil War.” That article evaluates the authors’ theoretical argument—that oil’s presence in a subordinate minority group’s core territory encourages ethnic war—using statistical analyses. This new article assesses the same argument, including the causal mechanisms underpinning it, using qualitative case studies. It concludes that “oil has rarely been a deep cause of ethnic war” (359). “Does Oil Cause Ethnic War” also aims to evaluate the relative strengths and weaknesses of qualitative and quantitative methods, thereby contributing to an ongoing debate in political science/international relations.