QCA

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Qualitative Comparative Analysis (QCA) is a method introduced by the US sociologist Charles Ragin for the causal analysis of configurational data in the social sciences. Translated, QCA means something like qualitative comparative analysis. Initially mainly used in macro-sociology, the method has spread across the entire field of political science and found its way into business administration, management and organizational research, educational research and even environmental and health sciences.

Search target

The aim of QCA is to identify minimally necessary and sufficient conditions for the existence of a certain value of a categorical variable, which is generally called the outcome . Achieving this goal can be done with the help of various algorithms. The most famous among them is the Quine-McCluskey algorithm .

In a first step, the underlying data is aggregated in a so-called truth table . This consists of all possible combinations of the values ​​of all included exogenous variables , also referred to as so-called configurations , as well as a function value that results on the basis of the consistency measure. In the second step, the disjunction of those configurations is minimized which have a positive function value, that is, which have been classified as sufficient with regard to the outcome. This minimization process continues until no further eliminations of variables are possible. The terms that remain at the end of this process are called prime implicants. The third step of QCA based on the Quine-McCluskey method consists of resolving the table of prime implicants, which contains the prime implicants in the rows and the configurations with a positive function value in the columns. This table is now resolved in such a way that all disjunctions of prime implicants are identified in such a way that no configuration with a positive function value remains uncovered and the disjunction thus found consists of a minimal number of disjoints. Such models are called minimal sums . However, since the minimal sum criterion produces false conclusions in the context of causal data analyzes, it is circumvented, more or less rigorously, by the usual computer programs.

variants

In the meantime, QCA has become a collective term for a family of configurational comparative techniques. This includes crisp-set QCA (csQCA), fuzzy-set QCA (fsQCA), multi-value QCA (mvQCA) and generalized-set QCA (gsQCA). All four variants differ from one another on the basis of the types of variables and quantities they process. Both csQCA and fsQCA are based on binary variables, the values ​​of which are the basis for sets in which objects can either only be elements or non-elements (csQCA) or may have partial memberships in these sets (fsQCA). With csQCA there are only two membership values: 0 and 1, while with fsQCA all values ​​can occur in the interval [0.1]. The main feature of mvQCA is the generalization of bivalent exogenous variables to multivalued variables. However, as with csQCA, the membership of objects in sets based on the values ​​of such a variable is only present or not present (0 or 1). This restriction is lifted by gsQCA, because this procedure also allows strictly partial membership values ​​of an object in all sets that can be formed based on the values ​​of multivalued variables. Thus, gsQCA combines all other three variants of QCA as special cases, while fsQCA and mvQCA represent generalizations of csQCA, the former on the dimension of membership values, the latter on the dimension of variable values.

software

There are several programs for the computer-aided implementation of QCA. Those with a graphical user interface include fs / QCA, Tosmana, and Kirq. These programs offer the advantage of quick familiarization, but are also less flexible in their options and in some cases have proven errors that have not yet been remedied. Alternatively, there are the command line programs QCA and QCA3 for the free R environment , as well as fuzzy for the commercial statistics program Stata .

further reading

Textbooks and basics

  • Grofman, Bernard, and Carsten Q. Schneider (2009): An Introduction to Crisp Set QCA, with a Comparison to Binary Logistic Regression. In: Political Research Quarterly, 62 (4): pp. 662-72.
  • Ragin, Charles C. (1987): The Comparative Method: Moving beyond Qualitative and Quantitative Strategies. Berkeley: University of California Press.
  • Ragin, Charles C. (2000): Fuzzy-Set Social Science . Chicago: University of Chicago Press.
  • Ragin, Charles C. (2008): Redesigning Social Inquiry: Fuzzy Sets and Beyond. Chicago: University of Chicago Press.
  • Rihoux, Benoît, and Charles C. Ragin, eds. (2009) Configurational Comparative Methods: Qualitative Comparative Analysis (QCA) and Related Techniques. London: SAGE.
  • Schneider, Carsten Q., and Claudius Wagemann (2012): Set-Theoretic Methods for the Social Sciences: A Guide to Qualitative Comparative Analysis (QCA). Cambridge: Cambridge University Press.

Special topics

  • Amenta, Edwin, and Jane D. Poulsen (1994): Where to Begin: A Survey of Five Approaches to Selecting Independent Variables for Qualitative Comparative Analysis. In: Sociological Methods & Research 23 (1): pp. 22-53.
  • Baumgartner, Michael (2009): Inferring Causal Complexity. In: Sociological Methods & Research 38 (1): pp. 71-101.
  • Caren, Neal, and Aaron Panofsky (2005): TQCA: A Technique for Adding Temporality to Qualitative Comparative Analysis. In: Sociological Methods & Research, 34 (2): pp. 147-72.
  • Eliason, Scott R., and Robin Stryker (2009): Goodness-of-Fit Tests and Descriptive Measures in Fuzzy-Set Analysis. In: Sociological Methods & Research, 38 (1): pp 102-46.
  • Ragin, Charles C. (2006): Set Relations in Social Research: Evaluating Their Consistency and Coverage. In: Political Analysis, 14 (3): pp. 291-310.
  • Ragin, Charles C., and Sarah Ilene Strand (2008): Using Qualitative Comparative Analysis to Study Causal Order: Comment on Caren and Panofsky (2005). In: Sociological Methods & Research, 36 (4): pp. 431-41.
  • Schneider, Carsten Q., and Claudius Wagemann (2006): Reducing Complexity in Qualitative Comparative Analysis (QCA): Remote and Proximate Factors and the Consolidation of Democracy. In: European Journal of Political Research, 45 (5): pp. 751-86.
  • Seawright, Jason (2005): Qualitative Comparative Analysis vis-à-vis regression. In: Studies in Comparative International Development, 40 (1): pp. 3–26.
  • Skaaning, Svend-Erik (2011): Assessing the Robustness of Crisp-Set and Fuzzy-Set QCA Results. In: Sociological Methods & Research, 40 (2): pp. 391-408.
  • Thiem, Alrik (2013): Clearly Crisp, and Not Fuzzy: A Reassessment of the (Putative) Pitfalls of Multi-Value QCA. In: Field Methods, 25 (2): pp. 197-207.
  • Thiem, Alrik (2014): Unifying Configurational Comparative Methods: Generalized-Set Qualitative Comparative Analysis. In: Sociological Methods & Research, 43 (2): pp. 313-37.
  • Thiem, Alrik (2014): Membership Function Sensitivity of Descriptive Statistics in Fuzzy-Set Relations. In: International Journal of Social Research Methodology, 17 (6): pp. 625-42.
  • Thiem, Alrik (2014): Navigating the Complexities of Qualitative Comparative Analysis: Case Numbers, Necessity Relations, and Model Ambiguities. In: Evaluation Review, 38 (6): pp. 487-513.
  • Vis, Barbara (2012): The Comparative Advantages of fsQCA and Regression Analysis for Moderately Large-N Analyzes. In: Sociological Methods & Research, 41 (1): 168-98.
  • Wagemann, Claudius, and Carsten Q. Schneider (2010): Qualitative Comparative Analysis (QCA) and Fuzzy-Sets: Agenda for a Research Approach and a Data Analysis Technique. In: Comparative Sociology, 9 (3): pp. 376-96.

software

  • Longest, Kyle C., and Stephen Vaisey (2008): fuzzy: A program for Performing Qualitative Comparative Analyzes (QCA) in Stata. In: Stata Journal, 8 (1): pp. 79-104.
  • Thiem, Alrik, and Adrian Duşa (2012): Introducing the QCA Package: A Market Analysis and Software Review. In: Qualitative & Multi-Method Research, 10 (2): pp. 45–9.
  • Thiem, Alrik, and Adrian Duşa (2013): Qualitative Comparative Analysis with R: A User's Guide . New York: Springer.
  • Thiem, Alrik, and Adrian Duşa (2013): QCA: A Package for Qualitative Comparative Analysis. In: The R Journal, 5 (1): pp. 87-97.
  • Thiem, Alrik, and Adrian Duşa (2013): Boolean Minimization in Social Science Research: A Review of Current Software for Qualitative Comparative Analysis (QCA). In: Social Science Computer Review 31 (4): pp. 505-21.

Web links

Individual evidence

  1. ^ Charles C. Ragin: The Comparative Method: Moving beyond Qualitative and Quantitative Strategies . Berkeley: University of California Press, 1987.
  2. ↑ http://www.compasss.org/bibdata.htm , accessed January 19, 2015.
  3. ^ Edward J. McCluskey (1956): Minimization of Boolean Functions. In: Bell Systems Technical Journal, 35 (6): pp. 1417-44.
  4. ^ Charles C. Ragin (2006): Set Relations in Social Research: Evaluating Their Consistency and Coverage. In: Political Analysis, 14 (3): pp. 291-310.
  5. ↑ Benoît Rihoux, Gisèle De Meur (2009): Crisp-Set Qualitative Comparative Analysis (csQCA). In: Configurational Comparative Methods: Qualitative Comparative Analysis (QCA) and Related Techniques. Edited by B. Rihoux and CC Ragin. London: SAGE, pp. 33-68.
  6. ^ Charles C. Ragin (2008): Redesigning Social Inquiry: Fuzzy Sets and Beyond . Chicago: University of Chicago Press.
  7. ↑ Lasse Cronqvist, Dirk Berg-Schlosser (2009): Multi-Value QCA (mvQCA). In: Configurational Comparative Methods: Qualitative Comparative Analysis (QCA) and Related Techniques. Edited by B. Rihoux and CC Ragin. London: Sage Publications, pp. 69-86.
  8. ↑ Alrik Thiem (2014): Unifying Configurational Comparative Methods: Generalized-Set Qualitative Comparative Analysis. In: Sociological Methods & Research, 43 (2): pp. 313-37.
  9. ^ Charles C. Ragin (2000): Fuzzy Set Social Science. Chicago: University of Chicago Press.
  10. ^ Charles C. Ragin, Sean Davey (2014): fs / QCA: Fuzzy-Set / Qualitative Comparative Analysis, Version 2.5. Irvine: Department of Sociology, University of California.
  11. ^ Lasse Cronqvist (2011): Tosmana: Tool for Small-N Analysis, Version 1.3.2.0. Trier: University of Trier.
  12. ↑ Christopher Reichert, Claude Rubinson (2014): Kirq, Version 2.1.12. Houston, TX: University of Houston-Downtown.
  13. ↑ Alrik Thiem, Adrian Duşa (2013): Boolean Minimization in Social Science Research: A Review of Current Software for Qualitative Comparative Analysis (QCA). In: Social Science Computer Review, 31 (4): pp. 505-21.
  14. ↑ Adrian Duşa, Alrik Thiem (2014): QCA: A Package for Qualitative Comparative Analysis, R Package Version 1.1-4. URL: http://cran.r-project.org/package=QCA .
  15. ↑ Ronggui Huang (2014): QCA3: Yet another Package for Qualitative Comparative Analysis, R Package Version 0.0-7. URL: http://cran.r-project.org/package=QCA3 .
  16. ↑ Kyle C. Longest, Stephen Vaisey (2008): Fuzzy: A program for Performing Qualitative Comparative Analyzes (QCA) in Stata. In: Stata Journal, 8 (1): pp. 79-104.