But Not Both: The Exclusive Disjunction in Qualitative Comparative Analysis (QCA)

Research output: Contribution to journalArticlepeer-review

441 Downloads (Pure)

Abstract

The application of Boolean logic using qualitative comparative analysis (QCA) is becoming more frequent in political science but is still in its relative infancy. Boolean ‘AND’ and ‘OR’ are used to express and simplify combinations of necessary and sufficient conditions. This paper draws out a distinction overlooked by the QCA literature: the difference between inclusive- and exclusive-or (OR and XOR). It demonstrates that many scholars who have used the Boolean OR in fact mean XOR, discusses the implications of this confusion, and explains the applications of XOR to QCA. Although XOR can be expressed in terms of OR and AND, explicit use of XOR has several advantages: it mirrors natural language closely, extends our understanding of equifinality and deals with mutually exclusive clusters of sufficiency conditions. XOR deserves explicit treatment within QCA because it emphasizes precisely the values that make QCA attractive to political scientists: contextualization, confounding variables, and multiple and conjunctural causation.
Original languageEnglish
Pages (from-to)75-92
Number of pages18
JournalQuality & Quantity
Volume49
Issue number1
Early online date5 Dec 2013
DOIs
Publication statusPublished - Jan 2015

Cite this