The Sweet Spot in Comparative Area Studies: Embracing Causal Complexity through the Identification of Both Systematic and Unsystematic Variables and Mechanisms Marissa Brookes University of California, Riverside T he tremendous value of Comparative Area Studies (CAS) is diffcult to overstate, as CAS scholars appear to accomplish the impossible: reaching broad-ranging conclusions from cross-case comparisons spanning two or more geographic regions, while still incorporating the sort of deep and detailed knowledge of people and places that is the hallmark of classic area studies. CAS researchers not only showcase the approach’s great strengths; they also encourage more work along these lines, since CAS contributions comprise only around 15 percent of recent works in comparative politics (Ahram, Köllner, and Sil 2018, 17). With this encouragement comes some welcome advice, including a push for more precisely conceptualized variables so that they are portable across contexts, admonitions against the assumption that geographic proximity defnes the full population of cases to which one’s theory applies, and a reminder that idiosyncratic factors are no less important than systematic conditions when it comes to causal explanation. This essay offers additional advice to enhance the CAS approach, starting from the premise that Comparative Area Studies’ greatest strength is also its main challenge: striking a balance between fully context-sensitive case studies, and the development of generalizable causal theories. I argue that CAS scholars can better balance these idiographic and nomothetic goals through more careful consideration of the logic of causal inference guiding one’s research. In particular, CAS scholarship would beneft not only from more explicit attention to whether explanatory variables found to travel across regions are necessary, suffcient, INUS, or SUIN, but also from a more conscious effort to determine whether or not the causal mechanisms linking explanatory variables to outcomes also travel across regions. In other words, does X 1 cause Y 1 in the same way in one region or area as it does in another? Good qualitative hypothesis testing typically entails two things: establishing the casual importance of variables that cases have in common through cross-case analysis and identifying the mechanisms that link those variables to the outcome of interest through within-case process tracing. For the frst task, CAS scholars seek to test whether a causal theory that explains cases in one region or area also explains cases in regions or areas other than the one in which that theory was initially developed. Yet it is not always clear what it means for a theory to “travel” across areas. For instance, if X 1 , X 2 , and X 3 are found to cause Y 1 in cases in Southeast Asia, should CAS researchers reject the cross-regional generalizability of the causal theory if they fnd that X 1 and X 2 , but not X 3 , are causally signifcant for Y 1 in cases in Latin America? Part of the problem is that assessing a theory’s generalizability is not as simple as determining whether X 1 , X 2 , or X 3 is present or absent across all cases with the outcome Y 1. Here is where more careful attention to the nature of explanatory variables in relation to each other and to the outcome can help. In particular, CAS scholars should frst specify whether the explanatory variables under consideration are necessary, suffcient, INUS (an insuffcient but necessary part of a larger cause that is itself suffcient but unnecessary), or SUIN (a suffcient but unnecessary part of a larger cause that is itself insuffcient but necessary) (Mahoney, Koivu, and Kimball 2009). Doing so would allow the researcher to then consider whether his or her causal theory is cross-regionally generalizable—meaning applicable to cases in more than one world region— despite cases examined in the second region not having the exact same combination of explanatory variables as the cases examined in the frst region. For instance, in the example above, failing to fnd X 3 in any of the Latin American cases would not render the causal theory inapplicable to Latin America if X 3 is only a suffcient, but not necessary, cause of Y 1 in the Southeast Asian cases. Likewise, consider the possibility of X 3 being an INUS variable, as in the following causal equation: Qualitative and Multi-Method Research 2020, Vol. 17-18, No.1 https://DOI: 10.5281/zenodo.3946805 20 | Comparative Area Studies Symposium