This edited volume continues the recent trend of synthetic research and meta-analysis in the field of applied linguistics started in large part by the editors themselves (Norris & Ortega, Reference Norris and Ortega2000; see also Goldschneider & DeKeyser, Reference Goldschneider and DeKeyser2001; Masgoret & Gardner, Reference Masgoret and Gardner2003). The volume is divided into three sections—introduction, research syntheses, and commentaries—with each section containing a varying number of chapters. The introduction section contains only one chapter, by Norris and Ortega, that provides a clear rationale for synthetic research as well as explicit information for conducting such research. The second section comprises the bulk of the volume, with seven chapters representing the application of synthetic research to various areas of applied linguistics research. Topics include Universal Grammar principles and parameters (Dinsmore), task-based interaction (Keck, Iberri-Shea, Tracy-Ventura, & Wa-Mbaleka), corrective feedback (Russell & Spada), interlanguage pragmatic development (Jeon & Kaya), second language (L2) reading comprehension (Taylor, Stevens, & Asher), effective teaching practices (Téllez & Waxman), and the assessment of L2 proficiency (Thomas). Five of the studies are meta-analyses that take a rigorous statistical approach to their topic, whereas the remaining two illustrate other approaches, such as a meta-analysis of qualitative research (Téllez & Waxman) and a research synthesis and historiography (Thomas). The third section consists of two commentaries (Chaudron; Ellis) that explore the advantages and disadvantages of conducting synthetic research in general and also comment on these issues in relation to the studies presented in the volume. Additionally, these final chapters consider the implications and future of synthetic research for our discipline.
The strengths of this volume are twofold: First, it is clear from many of the chapters that a well-written meta-analysis can provide a state-of-the-art picture of a given area of research. By methodically analyzing all of the relevant studies on a given topic, researchers are able to provide insights that a less systematic sampling of the data might overlook. For example, the chapter by Russell and Spada provides an excellent summary of issues regarding corrective feedback, including oral versus written, explicit versus implicit, and teacher versus peer feedback. The chapter also identifies aspects of corrective feedback, such as context, type, and focus, that have been underresearched. Another example is Thomas's thorough synthesis of the methods by which L2 proficiency has been operationalized in SLA research over the past 20 years. Such chapters help us take stock of where we are in the field, and I anticipate that many of these chapters will be frequently referenced as researchers pursue research agendas highlighted in them. Nevertheless, given the wide range of topics synthesized in this volume, individual readers might find only one or two chapters that inform their own research agendas.
The second, and perhaps most important, strength of this volume is as a methodological guide for conducting research syntheses and meta-analyses. The volume begins with a detailed discussion of the reasons and methods for doing such research, and throughout the chapters, there is considerable additional information. In fact, the empirical studies go to great lengths to document the procedures used in their analyses, and, indeed, such methodological transparency is an important component of synthetic research. Thus, anyone who is interested in conducting a meta-analysis will find this an invaluable volume, both as an instruction manual and as an example of the final product.
However, as I read through the chapters, I found myself questioning whether our relatively young discipline of applied linguistics, and especially language learning and teaching, is ready for a flurry of meta-analyses. Most of the analyses included in the volume were reduced to sample sizes of between 13 and 25 studies by the time the strict criteria for synthetic research had been applied. Only Thomas's synthesis on the assessment of L2 proficiency included a substantial number of studies (n = 157). To the volume's credit, the issue of small sample size as well as other limitations of synthetic research is squarely addressed throughout the volume and particularly in the commentary chapters.
In the first chapter, Norris and Ortega state that “this first generation of syntheses should probably set more modest goals of staking out the territory and raising awareness” (p. 45). This volume clearly attains these goals and provides a firm foundation for future generations of synthetic research in our field.
