Empirical Tests with Fuzzy-Set Qca

This chapter examines the book's theory further by using fuzzy-set qualitative comparative analysis methods, which test for necessary and sufficient causal relationships using the logic of set theory. The data confirm the hypothesis that both the petroleum deficit and the threat to imports must be substantial to trigger anticipatory strategies. Thus, the results reinforce the findings from the previous chapters that coercive vulnerability, as determined by the petroleum deficit and import disruption threat, spurs great powers to adopt anticipatory strategies to reduce the danger of oil coercion. Moreover, the severity of the strategy chosen is consistent with the level of coercive vulnerability faced by the state. The more extreme the deficit and import disruption threat, the more extreme the strategy chosen; the less extreme the deficit and threat, the less extreme the strategy chosen.