Publication Type: Conference Paper/Unpublished Manuscript Abstract: In recent decades, understanding terrorism and devising effective counter-terrorist strategies has become a top priority of national security decision-makers and the academia. Yet, at present there exists no agreed-upon definition of what constitutes terrorism. Consequently, scholars face a number of crippling substantive and methodological issues (conceptual stretching, indeterminate population boundaries, inability to generalize, biased inferences). This paper combines Giovanni Sartori's concept of the "ladder of generality" with the logic underlying Linnaean binomial taxonomy to offer a framework for thinking about constructing cases and populations for comparative research.