Abstract
If a potential reader overlooks the subtitle of this book by Gerrits and Verweij, then they might be surprised by its intent. Yet, the authors clear up its focus in the opening paragraph of the first chapter—complex infrastructure projects demand research methods that match their multifaceted and intricate nature, and qualitative comparative analysis (QCA) fits this need. Gerrits and Verweij argue that three attributes of complex infrastructure projects: heterogeneity, uniqueness, and context, limit the capacity of singular (or even multiple) case study designs and large-n studies to analyze and explain phenomena in such projects. The authors describe the mismatch between these more well-known methods and infrastructure projects as a “conundrum” and propose QCA as its solution—a method that selects cases, identifies conditions and outcomes associated with these cases, and uncovers combinations of conditions that generate outcomes.
A reader may not fully agree with Gerrits and Verweij because, for instance, well-done multiple case study research can identify generalizable patterns among cases (Eisenhardt, 1989), whereas statistical research can uncover important and specific insights about a subject (Aschauer, 1989)—and the authors acknowledge as much. A reader, however, will find it more difficult to contest the contribution of this book to the literature about QCA and its applicability to infrastructure research. Gerrits and Verweij have provided a comprehensive description of how and why to use QCA, which is a welcome complement to existing papers and books about its utilization. Since Ragin’s introduction of the method in 1987, QCA has gradually found its way into studies of infrastructure and construction, and Gerrits and Verweij document a number of such studies done in the first and second decades of the 21st century. To employ the method, these researchers either had to work their way through Ragin’s detailed accounts of the method (Ragin, 1987, 1998) or, more likely, rely on other descriptions such as Rihoux and Ragin (2009) that describes QCA through a series of edited chapters.
Now, infrastructure researchers seeking to use the approach or to learn more about it can turn to this book. Gerrits and Verweij do well to balance description and examples of QCA in a volume that can be read—but not fully deciphered—in a short period of time. The authors explain the logic behind QCA quite well, stressing that QCA is configuration oriented, a point made frequently by others. However, their emphasis on the concept of conjunction is particularly useful for those unfamiliar with the method. In their second chapter, which explains the importance and use of cases, they write, cases are characterized by causal complexity: (1) outcomes are produced by a coming together of factors, i.e. conjunctions of conditions (conjunctural causation); (2) and these conjunctions can be equifinal in that they are different but mutually non-exclusive explanations for the same outcome of interest (equifinality) (Scheider & Wagemann, 2012).
The notion of “conjunction” is quite important because researchers accustomed to statistical methods generally consider interactions between variables. Yet, conjunction is quite different; specific conditions are likely interwoven (or configured) to cause outcomes. Such distinctions about the tenets, as well as the nuances, of QCA are made throughout the book.
Aside from highlighting the underpinnings of QCA, Gerrits and Verweij have logically organized the book to follow implementation of the method. As mentioned, Chapter 2 focuses on cases, starting with a general discussion and then moving to a more specific discussion about how to select and develop them for QCA. Chapter 3 describes calibration of case conditions and examines the three primary types in QCA: crisp-sets, fuzzy-sets, and multi-value. Chapter 4 explains comparison, which is fundamental to deriving patterns across cases. Here, the authors introduce the reader to truth tables and the process for their minimization (or solution) as well as how to deal with common issues such as logical contradictions. They also endorse existing software to support QCA because such software helps to systematize use of the method. However, Gerrits and Verweij make a very important point about understanding its logic and steps: “QCA is not a press-button method. Instead, it involves many case- and theory-informed decisions by the researcher that can impact the final output, decisions that are easily obscured by clicking buttons in a software program.” Indeed, researchers who have not done their due diligence and do not understand the logic and processes of QCA will likely find the software output worthless or exceptionally difficult to interpret. In addition, throughout these chapters, the authors provide examples with enough depth and commentary to either instruct a novice with the method or to further inform a more seasoned researcher. The final chapter of the book explains how to account for time with QCA, and it provides some experienced advice about matters such as how to present results and to handle skeptics who are unfamiliar with the method.
Certainly, this book by Gerrits and Verweij is an important contribution to the infrastructure community in at least two respects. First, those considering QCA as a means to examine complex infrastructure projects can readily use this work to implement the method because the examples of past research on such projects makes it a more accessible reference than most existing works; although a single, consistent example demonstrating implementation of the method would have been useful, the authors give enough illustrative guidance. Second, many in the infrastructure community do not understand QCA, so they question its veracity; Gerrits and Verweij have delivered a concise but thorough description of it. Consequently, anyone wanting to understand it can do so with a modest investment of their time. The latter is likely more valuable because it increases the community’s awareness of research methods that can heighten comprehension of strategies for infrastructure development and management.