A comprehensive and accessible guide to learning and successfully applying QCASocial phenomena can rarely be attributed to single causesinstead they typically stem from a myriad of interwoven factors that are often difficult to untangle. Drawing on set theory and the language of necessary and sufficient conditions qualitative comparative analysis QCA is ideally suited to capturing this causal complexity. A casebased research method QCA regards cases as combinations of conditions and compares the conditions of each case in a structured way to identify the necessary and sufficient conditions for an outcome.Qualitative Comparative Analysis An Introduction to Research Design and Application is a comprehensive guide to QCA.