Keywords

1 Introduction

Theories are a fundamental aspect of scientific research and researchers have been investigating teaching for decades, but to date there has been no concerted effort to discuss whether there are valid theories of teaching, how a theory of teaching should be defined, what purpose it should have, what it should include, or how it should be developed. This book aimed to initiate a discussion of these topics by inviting internationally recognized scholars in the field to contribute their thoughts on the theorizing of teaching (see Chaps. 2, 3, 4, 5, 6, 7, 8 and 9). The contributors were asked to focus on a particular set of questions (see Chap. 1) and to participate in a Delphi study where they reflected on some of the other contributors’ answers (see Chap. 10). In addition to providing an up-to-date overview of how teaching is theorized, the purpose of this volume was to contribute to the further development of theories so that we better understand teaching.

The literature on the theorizing of teaching is extensive and no single volume could possibly address the whole subject. Bikner-Ahsbahs and Prediger (2010) suggested that a productive way to consider multiple theories of teaching would be to make sure that there is some overlap in the assumptions underlying the theories. Because of our background, we selected authors who had demonstrated an instrumental view of teaching in their work (cf. Herbst & Chazan, 2017) and enriched this view with some other perspectives.Footnote 1

In this chapter we synthesize and identify the patterns in the ideas presented in the contributions and, the implications of their findings; we also consider how the field can proceed to further develop theories of teaching in the future. Although this is a genuine attempt to consider the full contents of the volume, we have had to abridge the contributors’ ideas when summarizing, as providing an in-depth discussion of every idea would not have been possible (for a discussion of the limitations of this endeavor, see Sect. 9). The issues discussed in this chapter are: Why do we need theories and how can we define them (Sect. 2)? Do theories of teaching exist and if so, what are their foci (Sect. 3)? What are their key attributes (Sect. 4)? How can we develop theories of teaching and are comprehensive theories possible (Sect. 5)? Do theories of teaching need to account for content and context (Sect. 6)? What is the role of practitioners and practice in theories of teaching (Sect. 7)? What can the thought exercise in this book teach us about theorizing teaching (Sect. 8)? What are the limitations of the approach taken in this book (Sect. 9)? What general conclusions can one draw from this exercise (Sect. 10)? We believe that providing opportunities for discussion among scholars in the field is critical for the advancement of theories of teaching, therefore we discuss this issue throughout the chapter. We would like to stress, however, that the purpose of discussion is not to homogenize the field. Rather, we believe that discussion can help us to better understand each other’s perspectives and work and thus develop a better understanding of our own work—a key requirement for bringing together theoretical perspectives (cf. Prediger et al., 2008).

2 The Purposes and Definitions of Theories of Teaching

In our introduction to the book (see Praetorius & Charalambous, this volume)Footnote 2 we reviewed the reasons for which theories are crucial for scientific research on teaching. We noted that discussions about the need for theories of teaching were mostly found in publications dated before 1980 and questioned whether the consensus in the field was that no more work on theorizing teaching was needed. This is clearly not the case; in Chaps. 2, 3, 4, 5, 6, 7, 8 and 9 the contributors provided many important reasons why theories of teaching may be indispensable.

The contributors suggested that theories of teaching were useful for describing, explaining, and predicting, emphasizing the importance of explanation. One kind of explaining is causal explanations, which is inherent to the educational effectiveness approach (see e.g., Scheerens, this volume), but vehemently challenged by authors who focus more on educational theory (Biesta, this volume). A significant point of controversy between contributors was whether theories should be designed to improve practice (see also Sect. 7). Some authors stated that they should be (Cai et al., this volume; Hiebert & Stigler, this volume; Kyriakides et al., this volume), while others argued for using theories to improve research (Herbst & Chazan, this volume; Schoenfeld, this volume).

Looking at definitions of theories, we can see a similar heterogeneity. In Chap. 1 we provided an overview of definitions of theories of teaching based on a literature review. We showed that all of the definitions emphasized the systematic organization of concepts as a central element of theories of teaching. However, the definitions then each included different elements (listed in Table 11.1), illustrating that there has been little progress since Snow wrote, almost 50 years ago, that there “appear to be almost as many definitions of theory as there are people concerned with theory” (Snow, 1973, p. 78). When the authors were asked to explain their understanding of theories of teaching, their responses ranged from explicit definitions to detailed explanations.

Table 11.1 Aspects of theory definitions covered by the individual chapters
Full size table

The systematic organization of concepts can be taken to be a key aspect of theories of teaching since it was mentioned in all but one of the contributions (see Table 11.1) and in the definitions reviewed in our introduction.Footnote 3 Most contributors stated that theories should explain but fewer advocated that they should describe and predict. Some, but not all, chapters noted that theories should allow for generalizations and explain the relationships between concepts. These differences resulted in an array of views of what counts as a theory. For example, the direct teaching approach is cited by Scheerens (this volume) as an example of what he calls a partial theory whereas Herbst and Chazan (this volume) do not consider it a theory at all.

Vieluf and Klieme (this volume) highlighted two meta-theoretical aspects of theories which were not mentioned in Chap. 1, noting that (1) theories are socially constructed and (2) definitions of the term theory differ depending on epistemological and ontological perspectives.

Comparing the different chapters also revealed that theories have different grain sizes (see Cai et al., this volume), ranging from small (Hiebert & Stigler, this volume), to middle (Herbst & Chazan, this volume) to meta-level theories (Scheerens, this volume), an issue to which we return below. Because the authors understand the terms in different ways, further discussions are necessary to disentangle their specific comparative meanings both within and across paradigms.Footnote 4

Theories of teaching are formulated to serve a variety of purposes and are likely to have differing underlying assumptions so it is hardly surprising that the answers to the other four questions posed to the contributors also varied (see Sects. 3, 4, 5 and 6). Biesta wondered whether the authors’ answers to the other questions could be compared at all, as contributors had different views of the role of theories of teaching (see Chap. 10). Although we acknowledge these complexities, we are convinced that the ideas and reflections of the contributors provide a valuable starting point for a discussion on theorizing teaching.

Two related issues enable critical reflection on what the agreements and disagreements can suggest for future steps in theorizing teaching. First, because it forms the basis for all further discussion, researchers should clearly define their understanding of the purpose of a theory. Due to space restrictions and other policies of journals, this may not be possible in every research article, but it is important to include the information in theoretical papers, technical reports, or online materials. Second, because in research on teaching we often discuss many concepts/ statements without being explicit about their interrelations, in the future, we need to become more explicit about their similiarities and differences. In fact, Biesta (personal communication, April 1, 2021) suggested that if some kind of map of these statements could be provided, “apparent differences and perhaps even disagreements between the authors begin to disappear, as it seems that authors may be talking about different issues rather than that they have disagreeing views about the same issue.” If we succeed in developing such a map that allows the community to place different theories within it, the similarities and differences between them should be easier to identify.

3 The Existence of Theories of Teaching

As discussed in Chap. 1, since the 1960s opinion has been divided on whether theories of teaching exist. One group of scholars have either directly (e.g., Floden, 2001; Gage, 1963, 2009) or more tacitly (e.g., Snow, 1973) argued that theories of teaching do not exist. Writing in 1963, Gage argued that although there was a strong interest in developing theories of learning, theories of teaching were neglected or even deemed unnecessary on the grounds that “if we have an adequate theory of learning, then the teacher must of necessity act upon that theory, without employing any separate theory of teaching” (p. 133). Echoing this argument decades later, Gage (2009) lamented the fact that teaching was still the “stepchild” of theoretical work on teaching and learning. When he classified theories into different levels Snow (1973) suggested that it was not even possible to generate the highest level for teaching. Along similar lines, Floden (2001) argued that although a worthy goal, “a theory of teaching […] is unlikely to be attained in the near future” (p. 14). On the other hand, there are scholars (e.g., Biesta & Stengel, 2016; Klauer, 1985; Openshaw & Clarke, 1970; Oser & Baeriswyl, 2001; Philips, 2003) who assert that theories of teaching do exist, even though they do not always define them or provide examples.

Contributors were asked to comment on whether theories of teaching existed and to explain their thinking. Most maintained that they did, although, unsurprisingly given the many ways they defined theories (see Sect. 2), there was some disagreement. Biesta (this volume) made reference to a plethora of theories, rendering the identification of all of them a particularly challenging task. Similarly, Vieluf and Klieme (this volume) argued about the existence of multiple theories of teaching even within the same paradigm. Referring to theories of and for teaching in general, Cai and colleagues (this volume) also alluded to the existence of several theories.

Scheerens (this volume) made a distinction between different levels of theories. In his view, there are meta-theories concerned with the development, investigation or description of theory itself and substantive theories which are defined in relation to existing empirical findings. He further distinguished two subtypes of substantive theories, general theories and partial theories, with the first capturing a limited set of substantive teaching dimensions assumed to affect student learning and outcomes and the second corresponding to theories representing particular manifestations of the teaching-learning chain captured by the general theories. Scheerens (this volume) accepted that some of what he considered a theory might not be identified as such by others. Both in their prior work (Chazan et al., 2016; Herbst & Chazan, 2017; Silver & Herbst, 2007) and in this book, Herbst and Chazan (this volume) discussed the existence of multiple theories of teaching. Drawing on Merton (1949), they proposed a different classification of theories which included three types of theories, descending in size and complexity: grand, middle-range, and those based on specific hypotheses. Grand theories are “large sets of ideal constructs designed speculatively to be used to read the world” whereas specific hypotheses are “amenable to be tested empirically.” They classified their theory as middle-range, a “theory developed through the practice of research.” Linking two lines of his research, found in How We Think and his Teaching for Robust Understanding framework, Schoenfeld (this volume) argued that his work demonstrated the existence of theories of teaching. Overall, six of the eight chapters argued that theories of teaching exist. In four of those the authors either presented their work as an example of theory (Herbst & Chazan, this volume; Schoenfeld, this volume; Vieluf & Klieme, this volume) or named specific examples of theories of teaching (Scheerens, this volume). In the other two, the contributors referred to theories of teaching in rather broad strokes without naming any examples.

Taking a different stance, Kyriakides and colleagues (this volume) argued that although theories of teaching do not exist now, they could be developed. Presenting their work on the Dynamic Model of Educational Effectiveness, they argued that this model could gradually be turned into a comprehensive theory of teaching. Falling in the middle, Hiebert and Stigler (this volume) maintained that theories of teaching exist, but they are at a very nascent level and always in progress. They commented that “theories of teaching are necessarily so complex that they are only in progress; they are never complete” (p. 47). 

Clearly, almost six decades of academic study has not managed to resolve the question of whether theories of teaching exist. It was therefore not surprising that in their response to the Delphi study question about the extent to which consensus can be reached in the field of teaching, Cai and colleagues wondered: “Can we at least, reach consensus on whether we have theories of teaching?” (Chap. 10, p. 288). Despite its simplicity, this question seems rather difficult to answer as it requires agreement on several other questions, including what a theory should contain (i.e., attributes of theories) and why.

4 Attributes of Theories of Teaching

In this section, we consider the attributes of theories as identified by the contributors, beginning with those endorsed by most authors and moving on to those about which there was considerable disagreement.

While the contributors were not unanimously in agreement with any one of the 24 statements about the desirable attributes of theories presented in the Delphi study, there were three with which no one disagreed. They were that a theory should “explain basic terms,” “be specific enough to allow concrete connections among learning goals, teaching aspects, and student outcomes,” and “provide the means for expressing relationships among different aspects of teaching.” A fourth statement was disagreed with by only one contributor: A theory [of teaching] is informed by or grounded in epistemological preferences, paradigms, methodologies, and ontological considerations of theories in general” (Chap. 10). 

The four statements on the desirable traits of theories echo some of the criteria for evaluating the quality of a theory that were identified in the literature review in Chap. 1. For example, the first statement is essentially what the key sources in the review said 60 years ago, that theories should clearly define terms. The second statement also concurs with two attributes endorsed by two of the review sources - that theories should include quantitative and qualitative relations. The first captures how the sequence of teaching events can lead to student learning, and the second goes further to explore the mechanisms by which goals, teaching aspects, and student outcomes are linked. That both the literature review and the Delphi study converge on these attributes supports their fundamental importance and suggests that these attributes could serve as the basis for developing key features of theories of teaching.

Interestingly, there were some concerns raised by contributors about certain aspects of the statements discussed above. Below we focus on one key example to illustrate how the ensuing discussion can craft opportunities for productive discussions about theorizing teaching. When responding to the first statement, some authors (e.g., Cai et al., this volume; Kyriakides et al., this volume) argued that defining basic terms could result in non-parsimonious theories. While this might be a valid concern, we argue that defining key terms is a prerequisite of theories in general, and of theories of teaching in particular as prior work (Grossman & McDonald, 2008; Praetorius & Charalambous, 2018) suggests that terms in the field of teaching and teaching quality are not always used in a consistent manner.

What should be determined though, is which terms need to be explained. To initiate this discussion, we would argue that teaching and learning should be the first terms to consider, followed by teaching practice (cf. Herbst & Chazan, this volume) and learning opportunities (cf. Hiebert & Stigler, this volume): The term teaching practice is currently used in several different ways (see Lampert, 2010; Vieluf & Klieme, this volume) and warrants careful unpacking. Learning opportunities, on the other hand, can function as the intermediate link between teaching and student learning.

In discussing the importance of defining these terms, we are aware that there are objections to identifying learning as a key part of theories of teaching, since, as Biesta reminds us, not everything that happens in school is directly related to student learning, “learning is only one way in which students can relate to the world, and education should open up other ways of being and relating as well” (Chap. 10, p. 296). Biesta’s admonition to avoid referring to learning “without specifying what it is about and for” (Chap. 10, p. 296) resonates with the growing trend for a broader view of learning, moving from a rather restricted consideration of the cognitive and affective dimensions of learning to encompass meta-cognitive and psychomotor dimensions, as well as aspects of students’ well-being (physical and mental health), socio-emotional competence, and civic engagement (cf. Cappella et al., 2016; Reynolds et al., 2016). This example illustrates that exploring disagreements about theorizing teaching can also bring into focus how we explore the phenomena under consideration.

Opinions were clearly divided on nearly half of the statements about attributes of theories of teaching in the Delphi study. The divisive statements largely fall into two categories. The first category is statements about the content and function of theories of teaching and includes statements stipulating that a theory should contain empirically falsifiable propositions and experimentally falsifiable explanations, explain how teaching takes place, guide practitioners’ cause and effect reasoning in order to inform their instructional decisions, link teaching to its antecedents, and concurrently attend to issues of quality and equity.

Several factors contributed to disagreements about these statements. One was that some, especially those referring to the notions of falsifiable propositions and explanations, were not totally clear to all of the authors. As discussed in the previous chapter, this can partly be considered to be an artifact of the limitations of the Delphi approach as implemented in this book (see also Sect. 9). Since the contributors were not requested to read the other chapters in the book, they sometimes found it difficult to deduce the statements’ context. Some scholars from different paradigms or research traditions might also not have been very familiar with the terms we used to summarize and present ideas in the Delphi study. We argue that some of these disagreements might not be very problematic as they do not reflect deeper underlying philosophical assumptions. Offering scholars the opportunity to directly discuss such disagreements can provide insights into whether they are governed by underlying assumptions or if they can be resolved by discussing ambiguities in the terms used across research groups.

Other objections are more substantive since they concern fundamental questions about the purpose of theories. For example, Biesta made a strong case that “causality doesn’t exist in education” (Chap. 10, p. 296), and therefore disagreed with any statement that directly or indirectly assumes that causality does exist. Vieluf and Klieme (this volume) were also skeptical about causality based on Luhmann’s (1984) theory. This is, of course, in sharp contrast to perspectives entirely based on educational effectiveness research (e.g., Scheerens, this volume; Kyriakides et al., this volume) which are strongly supportive of causality.

Interestingly, in this category there were even disagreements about statements between scholars from the same paradigm. For example, Kyriakides and colleagues proposed that theories of teaching should concurrently attend to issues of quality and equity, but Scheerens disagreed, pointing out that although quality is a necessary concept within theories of teaching, asking for equity as well represents an unnecessary demand (Chap. 10). Such disagreements are interesting for what they might offer for the process of reaching consensus both within and across paradigms, a point to which we return later.

The second category of disagreement includes statements that largely capture how to organize, express, and represent theories. Included in this category are statements that stipulate that a theory of teaching should explain how instances of practice can be organized to form larger systems of practice (e.g., lessons, units, courses, and programs of study), include resources for representing the practice of teaching, include technical and non-technical language for describing the practice of teaching, and be expressed in a way that practitioners can easily evaluate. As in the previous category, there were a variety of reasons for the disagreements. Schoenfeld argued that, although important, such aspects should not be an integral part of theories, since they are concerned with communicating rather than describing a theory. Using the parallel of developing a theory in economics, Schoenfeld (Chap. 10, p. 300) explained:

The goals of a theory should be to (a) understand something; (b) to, if you wish to work in particular directions, specify what it takes to work in those directions. By way of metaphor: suppose I wanted to develop a theory of economics. The goal would be to specify how and why an economy works. Then, suppose I wanted to create an economy that eliminated poverty. That’s a value statement. I’d be identifying the subset of things, consistent with the general theory, that produced the desired outcomes. Those are (a) and (b). Communicating aspects of these effectively may be necessary to move in the desired directions, but they’re not part of the theory.

Cai and colleagues were also skeptical about the value of including technical terms in theories, worrying that doing so could lead to “obscuring plain meanings” and “prevent teachers from “easily being able to make use of theory without an unnecessary additional investment of time and energy to decode language” (Chap. 10, p. 298), a concern also echoed by Kyriakides and colleagues. In contrast, Vieluf and Klieme pointed out that focusing on ensuring that theories are expressed in ways that make them easy for practitioners to evaluate could be limiting given that this presupposes that theories are only developed for informing practice (see Chap. 10). Perspectives on the interplay between theory and practice and teachers’ role in understanding and using theories underlie these disagreements, an issue we discuss further in Sect. 7.

What do these disagreements tell us? We argue that identifying and classifying the source of any disagreement is an important first step since different reasons for disagreement require different approaches for a resolution. Disagreements based on deeper philosophical, epistemological, and methodological differences might be harder to address than those related to the clarification of ideas and definitions. The next step is to give scholars more opportunities for focused interactions around the theorizing of teaching. Taking the Delphi study in this book as beginning, we feel that further rounds of exchanges need to occur and that these need to be more interactive than the approach undertaken in this book.

Despite its limitations, the current Delphi study also offers some guidelines for how to improve. For example, the fact that scholars from the same research paradigm still disagreed on fundamental statements suggests that it might be more productive to initially aim for consensus within more homogeneous groups before moving to more heterogeneous groups where disagreements are more likely to arise. The third step would involve carefully analyzing persistent disagreements to understand their origins and examine whether it is realistic or worthwhile to try to resolve them within or across paradigms. In fact, discussions about such disagreements would probably be beneficial even if consensus is not possible, because they could help clarify our perspectives of educational phenomena. Unresolved disagreements need to be carefully codified, along with the reasons causing them.

5 Processes for Developing (Comprehensive) Theories of Teaching

Developing theories of teaching is a very complex activity and requires meta-theoretical work (Snow, 1973). In Chap. 1 we reviewed the literature on what such meta-theoretical processes could and should look like, but concluded that to date, the actual process of generating theories of teaching has not received much attention. Reviewing the ideas in the individual chapters and in the Delphi study, it seems that there is more agreement about the process of developing theories than there is about the attributes of theories (see Sect. 4). This might be because the process of developing theories is less dependent on the purpose and definition of theories of teaching than on its content. However, there are still important differences in how much contributors agree with statements related to the process of generating theories. It is therefore useful to group these into general statements that apply to any theory of teaching, independent of its purpose, definition, and content (first category), statements that reflect prevailing assumptions in certain research areas (second category), and statements that seem to be dependent on other, more specific issues (e.g., specific norms and values shared only within specific research groups; individual differences in the understanding of specific terms) (third category).

The responses to the most general statements, the first category, revealed that most participants agreed that good theory development requires that the underlying principles on which the theory is built be explicitly stated, the limitations of existing models/theories be acknowledged, and the scope of the theory generated be open to expansion. These statements provide a basic structure for developing theories further to a meta-level, as currently not all theories of research on teaching satisfy these conditions (see also Chap. 1).

Several statements in the Delphi study about the process of developing theories of teaching reflect prevailing assumptions in educational effectiveness and mathematics education research (second category). This is especially true of those that focus on hypothesis building and revision (“generate a concrete hypothesis” or “continuously test and revise predictions suggested by the hypothesis”), but also holds for the idea of generalization (“aggregate findings across classrooms and search for patterns that rise above specific contexts”). That the ratings for these statements are again not entirely consistent even for scholars within the same research area [e.g., Cai et al. (this volume) and Herbst and Chazan (this volume) differed on their level of agreement on these statements, something that was also true for Kyriakides et al. (this volume) and Scheerens (this volume), see Chap. 10], may be due to semantics.

The third category largely consists of statements that pertain to the relationship between research and practice (e.g., “find ways to create sustainable partnerships between teachers and researchers and build networks of partnerships“) and meta-statements (e.g., “reaching consensus on shared rules of engagement; dealing with tensions among sets of competing values such as ecumenism and consistency, complexity and parsimony”). Whether scholars agree with such statements seems to depend on reasons unrelated to their research specialism (for further analysis, see Sects. 7 and 8).

What the contributors found difficult for reaching an agreement about the process of theory development pertained to which terms were best for describing this process. For example, in his response to the first statement, Scheerens disagreed with the term commitment as this might also encompass political objectives which, in his view, would not be appropriate (Chap. 10), but he agreed with a similar statement about the attributes of theories (“A theory is informed by or grounded in epistemological preferences, paradigms, methodologies, and ontological considerations.”) that did not contain this term. This makes it clear that such disagreements about terminology could more easily be resolved in a discussion or more discursive exchange of ideas.

Researchers also disagreed with some of the ideas underlying the Delphi statements. For example, Hiebert and Stigler questioned the process of testing and refuting hypotheses (Chap. 10). They held that piecemeal tinkering to gradually refine and improve a theory, as proposed by Karl Popper, was preferable. Biesta meanwhile disagreed with any approach rooted in empirical research outcomes, skeptical that empirical data is suitable for the development of theories (Chap. 10).

Consequently, it would be fruitful to continue the discussion started in this book with further, more detailed, exchanges between research groups. In his contribution to the Delphi study (Chap. 10), Scheerens drew attention to the added-value of exchanges between researchers with different perspectives on teaching, such as the one in this book. Hiebert and Stigler commented that they found the Delphi approach useful for building on one another’s work in order to improve theoretical predictions (Chap. 10, p. 308):

We find it interesting that the same process used to create this chapter (a Delphi Study) would be especially useful for building on others’ work to improve predictions. If researchers were addressing the same problems, then comparing predictions and sharing data and rationales could help individual researchers—and the group as a whole, build from empirical outcomes to not only improve their predictions but increase the richness of their explanations or, said another way, their understanding of the problems they are investigating.

Such a process might be particularly useful for discussions in rather homogenous groups where sufficient agreement is expected to exist on the purpose of theories and on useful ways of investigating theories scientifically (e.g., different ways of using empirical data).

The contributors were also asked to reflect on whether, and if so, how a (more) comprehensive theory of teaching could be developed in the future. The authors’ answers were again divided. Some authors (Kyriakides et al., this volume; Scheerens, this volume; Schoenfeld, this volume) replied in the affirmative, either stating that their own theoretical work could evolve into a comprehensive theory (Kyriakides et al., this volume; Schoenfeld, this volume), or that meta-analyses and research reviews could facilitate the generation of one (Scheerens, this volume). Herbst and Chazan were optimistic that the field could move toward a more comprehensive theory of teaching, once a number of prerequisites were satisfied. Apart from making their commitment to certain underlying assumptions explicit (as discussed above), they also highlighted a set of facilitating conditions: The development of instruments that allow the gathering of information on competing constructs from different theories so that the relations between them can be compared and understood; the pre-registration of experiments that would allow different theories to compete (see a similar discussion in Charalambous et al., 2021); and the development and articulation of shared rules of engagement, such as recognition of the tensions that exist in theorizing teaching (complexity vs. parsimony, see Chap. 10).

Others argued that it is simply not possible to create a grand comprehensive theory of teaching. Cai and colleagues (this volume), for example, believe that although theories of teaching will develop over time because they will be connected to each other and also evolve to accommodate differences in subject matter, grade levels, and culture, a comprehensive theory is not possible. Rather, they maintain that it is reasonable to expect that teaching and theory will co-evolve with each informing and setting the ground for the evolution of the other. Vieluf and Klieme (this volume) anticipate that theories of teaching will move in the direction of diversification. They believe that as the existing theoretical paradigms increase in sophistication, they will further split into multiple theories per paradigm instead of converging into one grand theory Biesta (this volume) was not sure if convergence or divergence would be the pattern in the future, but highlighted the importance of restoring the balance between the discourse on teaching and the discourse on learning—alluding to the need to make teaching the key focus of our work instead of considering it only in conjunction with learning. Hiebert and Stigler (this volume) were also against the development of a grand comprehensive theory of teaching and argued for the importance of expanding on smaller theories.

In conclusion, the contributors to this book predict that theories of teaching will evolve in two possible directions. Either they will become more comprehensive and integrate existing theoretical conceptualizations or they will diversify. The affordances and limitations of both options merit further discussion in the future.

6 The Role of Content and Context in (Generating) Theories of Teaching

The contributors to this book were asked to discuss whether a theory of teaching can accommodate differences across subjects and student populations. We asked this question because although the writings from the 1960s to the 1980s were agnostic on the role of subject (see Chap. 1), strong arguments were made in the mid-1980s about the role of content in teaching (e.g., Romberg & Carpenter, 1986; Shulman, 1986). Chazan et al. (2016) also noted that in the last decades, content has moved from the background to the foreground in the study of teaching. We also considered arguments about the importance of differences in student populations (see, for example, Kennedy, 2010). Although, in hindsight, we recognize that a slightly different wording of this question (i.e., asking whether a theory should accommodate considerations of content and student population) could have led to an even a richer set of ideas, the authors’ answers to this question helped capture different perspectives about the role of content and context in theories of teaching, which we consider below.

The contributions to this book can be thought of as occupying different positions across a spectrum of the importance and role of content in theories of teaching. Unsurprisingly, these perspectives are consistent with the authors’ prior work. At one end of this spectrum is Biesta; Herbst and Chazan and Hiebert and Stigler sit at the other. Clearly articulating that his conceptualization of teaching is subject-matter independent, Biesta (this volume) argued that content should not be a concern in theories of teaching. Attention should be focused on three content-independent domains that capture, according to him, the role of teaching: the qualification, socialization and subjectification of students. Consistent with previous statements they have made, [e.g., in Herbst & Chazan, 2017 they called on the field “to increase the subject specificity of mathematics teaching”, p. 119], Herbst and Chazan (this volume) strongly endorsed the role of content. Without ruling out the possibility that the elements they used in their Practical Rationality theory (e.g., instructional exchanges, situations, and norms) have applicability beyond mathematics, their theory and body of work argue that content-specificity is an integral part of generating theories of teaching. Along similar lines, although Hiebert and Stigler (this volume) accepted the possibility that a generic theory of teaching that “swap[s] out subject matter” may help teachers “make and test instructional decisions” (p. 47), they argued that these decisions will remain general and vague. For them, the more useful theories are those developed with greater specificity, with content-specificity being one of the defining parameters. These differences in perspective tie in with the scholars’ body of work: whereas Biesta’s work transcends the borders of different subject matter, Herbst and Chazan as well as Hiebert and Stigler have largely studied teaching within the discipline of mathematics.

While also working in the field of mathematics, Schoenfeld appears to adopt a content-generic stance when it comes to the role of content in theories of teaching. For Schoenfeld (2011), the three building blocks of his theory of how teachers think—resources, goals, and orientations—cut across different subjects. Although indispensable for teaching, content can be considered as adding details to those three blocks. This is not surprising because Schoenfeld’s work (e.g., his “How We Think?” book and his Teaching for Robust Understanding framework), derives from studies in mathematics, but is considered to be applicable beyond the one subject.

For the remaining scholars, content-specificity appears to be a potentially important, but not integral aspect of theory generation. Although coming from a more content-generic perspective, as evidenced by their work on educational effectiveness research, Kyriakides et al. (this volume), Scheerens (this volume), and Vieluf and Klieme (this volume) endorsed looking for universalities/generalizations in their field, while acknowledging that there might be certain differences in teaching between subjects, what in prior work (Campbell et al., 2004; Scheerens, 2015, 2016), the first two author groups labeled differentiated effectiveness. According to this perspective, the “foundational concepts and explanatory mechanism of theories of teaching should be considered as working equally well across subject matter areas” (Scheerens, this volume, p. 124); content represents one of the parameters, alongside others such as the students and the working environment, that might moderate how teaching contributes to student learning. Cai and colleagues (this volume) deemed content-specificity important, although not as much so as Herbst and Chazan (this volume) or Hiebert and Stigler (this volume), accepting that there are conceptualizations of teaching, such as Resnick’s work on higher-order thinking, that appear to work well across subjects. Different groups of scholars, therefore, seem willing to embrace either content-generality or content-specificity regardless of their prior work, a point we elaborate upon below.

The authors were also asked to discuss whether theories of teaching can accommodate differences between students. Their responses largely mirrored their stances on the issue of content-specificity. For example, Biesta (this volume) talked about his theorization being student-independent, arguing that considering the student population and how teaching can be shaped to account for differences between students should be left to the “artistry of the teachers” (p. 277). Similarly, Schoenfeld (this volume) argued that although student composition matters since “[t]o be an effective teacher of any group of students, one needs to know those particular students and have a sense of what supports their learning” (p. 180), when developing theories of teaching differences across learners should not [be] prioritized; actually, he deemed such differences second-level elements (“details”) compared to the key building blocks of his theory. In contrast, Cai and colleagues (this volume) and Herbst and Chazan (this volume), ascribed a more central role to the student population, claiming that not just student population differences but also other contextual characteristics needed to be considered, a stance that resonates with the perspective of the practice theories paradigm discussed by Vieluf and Klieme (this volume). Specifically, Herbst and Chazan (this volume) asked that cultures and institutions also be considered, claiming that “At some level of theorization, a theory of teaching practice could take all those […] sources of difference and elaborate them theoretically” (p. 218). Similarly, accommodating both the Confucian tradition and Western beliefs about the role of teaching and teachers, Cai and colleagues (this volume) made a strong case for the role of context in theorizing teaching, writing that “teaching is […] shaped by cultural expectations, and, consequently, theories of teaching may naturally end up reflecting the cultural practices of the context in which they are conceived, used, and refined” (p. 238). 

One way to resolve these differences with respect to content and context might be to accept that, as suggested by Vieluf and Klieme (this volume), different paradigms often conceptualize educational phenomena differently. For example, when comparing and contrasting the teaching effectiveness research paradigm with the practice theories paradigm, Vieluf and Klieme (this volume) explain that while teaching effectiveness research “aims at explaining achievement test results with teaching, research from a practice theoretical perspective aims at understanding teaching in all its facets” (p. 75). In the first paradigm, the content and composition of the student population are two factors moderating the teaching-learning relation. In the second paradigm, they can play a more prominent role since they can shape how teaching unfolds, especially when teaching is viewed as interactions between the teacher and the students around specific content and situated in specific contexts (see Cohen et al., 2003).

Another way to handle these differences would be to offer scholars more systematic opportunities to discuss these differences in order to better understand why they might hold a more content/context agnostic or supportive perspective. We are convinced that continuing this dialogue can be beneficial, since we see some areas of convergence in the authors’ answers, even when their answers seem to be superficially quite different. This is exemplified by the way some content-generic authors accept the possible validity of content specificity and some content-specific authors acknowledging that content-specific attributes might have wider applicability in other subject areas. For example, when discussing the need to advance their work on the Dynamic Model of Educational Effectiveness (Creemers & Kyriakides, 2008), a content-generic model, Kyriakides and colleagues (this volume) argued for the importance of incorporating content-specific aspects into their work. Herbst and Chazan (this volume) entertained the idea of exploring the applicability of the building blocks of their content-specific Practical Rationality theory (Herbst & Chazan, 2003) in other subject matters. Hence, there seems to be a move toward the integration of the two views. This can couple with current attempts to enhance classroom observation instruments that move between the content generic and the specific, attempting to reap the benefits of each perspective (see, for example, the German special issue on content-specificity in research on teaching quality, Praetorius & Gräsel, 2021).

We do not wish to underplay the fact that most of the contributors to this book were associated with research in mathematics and that several of the authors associated with content-generic approaches have used mathematics as the main subject area in their investigations. Given the increasing heterogeneity in the field of research on teaching, we intentionally chose a homogeneous group of researchers to facilitate a first step in reaching consensus. Moving forward, a more diverse group of researchers, not only in terms of subject but also in terms of culture, language, or disciplinary background, needs to be involved.

7 The Role of Practitioners in Theorizing and Using Theories of Teaching

Although the questions that guided the development of this book did not refer to it explicitly, an important topic repeatedly emerged in the contributors’ answers: the role of practitioners in developing and using theories of teaching.

In line with their prior work (see, for example, the 2018 editorial co-authored by Cai, Hiebert, and other colleagues), two groups of contributors called for blending the traditional roles of researchers and teachers when generating theories of teaching. Hiebert and Stigler (this volume) proposed giving teachers a more prominent role in developing and testing hypotheses for teaching and learning. Building on their idea of the importance of creating sustained learning opportunities (SLO) for students, they write (p. 39):

Imagine teachers and researchers developing teams, or partnerships, to meet the challenge of creating theories of SLOs. The promise of researcher-practitioner partnerships has been realized in professional fields outside of education […] From auto manufacturing to the repair of Xerox machines to clinical medicine to the wind turbine industry, this multiple expertise model has been used effectively to improve practices across a range of professions […] When teachers and researchers form partnerships around shared problems of practice, they can realize similar successes […]

Using the terms “theory for teaching” and “teaching for theories,” Cai and colleagues (this volume) also saw researchers as working closely with teachers to co-develop and refine theories needed for the work of teaching. Using the example of creating teaching cases in a Chinese setting, they suggested that the continuous and spiraling opportunities teachers are provided with to create a lesson, implement it, and reflect on it, provide fertile soil for testing “small, local hypotheses about how attributes of tasks or instruction may influence students’ learning in the particular context” (p. 243), thus contributing to theory generation (for a similar argument, see Kyriakides et al. on McIntyre’s (1995) “practical theorizing”, see Chap. 10). And they continue, “the teaching case provides a dynamic, tangible resource that can help store this knowledge gained from teaching for theory and, in turn, allow teachers and researchers to use that knowledge to extend theory for teaching” (p. 243).

Unlike these two groups, who proposed that theories be co-generated through researcher-teacher collaboration, the authors of the remaining chapters do not directly address this issue, which is not surprising given that they were not asked to do so. However, there are some comments in their writing, either in their chapters or in their Delphi study replies, which could be considered indicative of their perspective on teachers’ roles in the development of theory.

Perhaps the most telling piece of evidence stems from comparing their responses to the three statements concerning the process of generating theories. The first stipulates that theories should be developed in ways that help teachers inform and improve their practice. All but one of the authors agreed with this, with Kyriakides and colleagues even contending that the ultimate goal of theory development is to inform practice (Chap. 10). The other two statements held that to develop and/or enrich theories of teaching, researchers needed to coordinate with teachers to test predictions and revise hypotheses and to build networks and create sustainable partnerships with practitioners. There was more disagreement with these two statements: in addition to explicit disagreements (one in each case), there were also a number of partial agreements (four to five). The level of disagreement might in part have been caused by issues of terminology (e.g., using terms such as networks and partnerships) that influenced some authors’ opinions (e.g., Scheerens). However, the range of responses to these statements compared to those for the first one makes us wonder whether the disagreement is also partly due to the different roles ascribed to teachers, with the first statement characterizing teachers as merely users of theories and the latter two ascribing a more active role to them based on productive teacher-researcher collaborations and partnerships. This conclusion is supported by the fact that, as discussed in Sect. 4, another statement which stipulated that theories need to be expressed in ways in which teachers can easily see their value also divided the contributors.

We see three distinct options for the role of practitioners in developing scientific theories.Footnote 5 We will call the first the consumer role. In this role it is not the teachers’ responsibility to develop theories of teaching; it is not even necessary for teachers to understand such theories or to judge their validity. Instead, teachers need to be exposed to any practical implications that certain theories of teaching might have for their work and be able to use those to improve their work and benefit their students. The second is the informed applicant role. As in the first role, teachers are not expected to develop theories of teaching however, unlike in their role as a consumer, they are expected to understand theories and consider their implications for their daily practice. The third is a co-developer role. In this role teachers are expected to be more active and work closely in collaboration with researchers to develop and refine theories of teaching.

Several statements in the contributions as well as in the Delphi study suggest that each of the three roles is favored by some authors. From their work it is clear that Cai and colleagues, Hiebert and Stigler, and Kyriakides and colleagues subscribe to the co-developer role for teachers (see Chap. 10). However, because this issue was not directly raised by us, we will not assume which option the other contributors preferred. There are arguments for all three options. Opponents of blending the roles of teachers and researchers could point out that teachers are often concerned with more local problems that relate to their daily practice, whereas researchers, when viewed through certain paradigms, are more concerned with producing work that transcends particular situational and historical contexts. Opponents could point out that practitioners themselves also hold theories, which are different from researchers’ scientific theories, in terms of theoretical grounding, level of generality, and empirical verification. Therefore, although continuous exchange between scholars and practitioners is desirable, seeking to co-develop theories might be dysfunctional.Footnote 6 Proponents of assigning teachers a more active role in the theorizing process might, on the other hand, counter that practitioners are in a better place than researchers to identify problems of daily practice and offer initial ideas for resolving them. These arguments show that the potential role of teachers in the process of theorizing and using theories warrants focused and explicit discussion among scholars. Teachers should also be invited to join the discussion to present their perspective on how they see their role in this process, and what they think it is feasible.

The role of teachers in theorizing teaching raises a number of other related issues. Herbst and Chazan as well as Schoenfeld point out that limiting ourselves to generating theories just for the sake of improving practice might result in producing prescriptive theories that stipulate how teaching should look in order to improve student learning. Producing such theories, Herbst and Chazan (Chap. 10) argue, is both limited and limiting in a field that aspires to be scientific. They wonder, “Are we committed to understanding scientifically the world of practice or are we just advocating for a particular vision for practice?” (p. 307). For them, the answer is the former and therefore we need descriptive and/or explanatory theories to guide research in ways that help develop and validate the existing scholarly knowledge. Vieluf and Klieme appear to concur with this stance, when, reflecting on a statement included in the Delphi study (“a theory should be expressible in ways that practitioners can judge its face validity”), they challenge the idea that the goal of developing theories is simply to inform practice. For them, ascribing such a focused role to theories imposes unnecessary restrictions on theorizing teaching (Chap. 10). Schoenfeld raises a related concern: when attempting to communicate theories to teachers, in order to improve practice, we are running the risk of rendering this communication a theory attribute. For him, this should not be the case, as he explains while commenting on a Delphi study statement: “Communicating useful ideas to teachers is essential for improvement, but it is not part of a theory of teaching, any more than telling people to conserve energy is […] a contribution to the theory of climate change” (Chap. 10, p. 306). These points actually raise a set of additional issues about the type of theories generated (prescriptive, descriptive, explanatory), and their attributes.

8 Theorizing Teaching: Looking Back and Looking Forward

In the introduction to this volume (Praetorius & Charalambous, this volume), we noted the significant variation in views on the subject of theorizing teaching among scholars and the apparent scarcity of attempts to initiate discussions that promote the exchange of ideas and consensus. We set out to conduct a directed discussion and improved the odds for a productive dialogue by selecting a relatively homogeneous group of academics. Despite being complex and demanding, we were convinced that this exercise was worthwhile since exchanges are crucial for enhancing our collective understanding of theorizing teaching (see Chap. 1). So have we learned anything new?

One could argue that this volume simply adds to the body of work confirming that there is a huge variation in how researchers view the theorizing teaching. In fact, as a reviewer opined, despite our attempts to establish some common ground, the chapters do not necessarily represent a collective “we”—and we agree. As the reviewer eloquently noted,

Some [chapters] seem to not agree on the nature of rigorous research. Some chapters seem to suggest that “scientific” research is quantitative and rigorous and empirical [...]. Some chapters seem aligned with a relatively technocratic idea of educational “effectiveness” […] versus a more generous, robust, or ambitious view that would include a range of proxies for measuring whether teachers and students did productive work together [...]. Some authors seem to embrace a view of theorizing the work of teaching as messy and variegated, others as searching for parsimonious lists of discrete, easily measured variables.

When reading the book one can hardly miss the differences in the authors’ viewpoints on the existence (or not) of theories of teaching, the process of developing theories, their attributes, and the extent to which they could or should accommodate differences across contexts and subjects.

Yet, we would argue that this volume is much more than a compilation of the wide range of opinions about teaching. To corroborate this argument, in this section, we discuss three lessons learned from this exercise and propose five steps for how to move forward.

The first lesson is that in order to better understand how theories are developing and be able to compare and contrast differing perspectives, the prerequisite is researcher making their work comprehensible to others and being able to understand the work of others (cf. the first two steps in the model of Bikner-Ahsbahs & Prediger, 2010). The importance of this prerequisite was confirmed when the contributors were asked to respond to the five questions that formed the backbone of the project (Chap. 1). They first outlined and then reflected on their own work (Chaps. 2, 3, 4, 5, 6, 7, 8 and 9), which ensured that they explained the underlying assumptions that guided their thinking. The attempt to then engage the contributors in an exchange (Chap. 10) showed both the importance of and the difficulties in understanding others’ work. The difficulties ranged from developing a vocabulary of terms—including some one might think were clear—to understanding, but not necessarily embracing, assumptions different from your own. Thus we agree wholeheartedly with Bikner-Ahsbahs and Prediger (2010) that significant effort should be invested in making one own’s work as clear and unambiguous as possible. This and the opportunity to interact often with others is necessary for more synergy in the field of theorizing teaching.

The second lesson concerns the issue of whether consensus can be reached on the issues around theorizing teaching which have been discussed in this volume. When we began the project we believed achieving consensus on the many complex aspects of theorizing teaching to be a desirable, important goal. However, the contributors’ answers to one question in the Delphi study raised the possibility that reaching consensus may not be optimal. Some authors favored consensus because it facilitates communication and exchanges about teaching (Scheerens, this volume), a common understanding of teaching (Hiebert & Stigler, this volume), and knowledge accumulation (Cai et al., this volume; Hiebert & Stigler, this volume). Others considered reaching complete consensus unlikely (Cai et al., this volume; Schoenfeld, this volume), questioned who might need consensus and for what purposes (Herbst & Chazan, this volume) or pointed out that the cultural embeddedness of teaching precludes the possibility of reaching consensus (Cai et al., this volume). Other obstacles to consensus put forward were that researchers have their own agendas (Kyriakides et al., this volume), that funding for such activities is currently limited (Herbst & Chazan, this volume), and that researchers need to be motivated to do such work (Herbst & Chazan, this volume). Overall, the contributors seemed to view reaching consensus as a worthwhile, if possibly unattainable goal. We accept this view given that we were unable to reach a consensus during an exercise that involved a relatively homogeneous group of researchers and focused on particular aspects of theorizing teaching. At the same time, we embrace some authors’ contention that even though it may not be possible to reach consensus across the entire research community, it may be possible within research paradigms (Hiebert & Stigler, this volume; Vieluf & Klieme, this volume). We revisit this idea when discussing the work that needs to be undertaken across and within given paradigms.

The third lesson involves a specific form of consensus—whether it is possible to develop a (more) comprehensive theory of teaching in the future. The contributors responses to this question were divided with some authors suggesting that existing theoretical work could evolve into such theories and others being opposed to the development of a comprehensive theory of teaching. This latter stance is also reflected in Bikner-Ahsbahs and Prediger’s (2010) paper which argues that attempts to develop global unified theories run the risk of homogenizing different ideas by regarding their diversity as an obstacle to scientific progress. Such a stance, “risks usurp[ing] the richness of theories by one dominant approach” (p. 491). Therefore, instead of attempting to develop one overarching theory, we believe that the theorizing of teaching would benefit from simultaneously moving in two different directions: diversifying as the existing paradigms grow in sophistication, as suggested by Vieluf and Klieme (this volume), and local synthesis and integration, as suggested by Bikner-Ahsbahs and Prediger (2010). According to the latter authors, although developing unified global theories might be neither realistic nor productive, attempting to build more local synergies between theories is a viable and worthwhile goal since it can help to advance a field scientifically. Theories which have compatible underlying philosophical assumptions can be brought together and integrated in ways that can produce new theories that can help to better understand issues in teaching.

Given the lessons learned, we would like to suggest five steps which are important for the future advancement of theorizing teaching. We identify those steps which appeared to work well in this exercise and could possibly be scaled-up in future, and those which need revision, extension or refinement.

  • Step 1

Selecting the research groups who would be asked to contribute to this book was our starting point. We assumed that inviting researchers who have focused on teaching quality would be a good starting point. We learned, however, that even scholars who apparently subscribe to similar approaches to studying teaching and learning can have significant differences. For example, we originally thought Kyriakides and colleagues and Vieluf and Klieme to be in a cluster since both groups focused on teaching effectiveness research, but their contributions revealed notable differences in their thinking, with Vieluf and Klieme moving a long way beyond ideas of teaching effectiveness. We are still convinced that inviting scholars with similar ideas is important, since otherwise, as Hiebert and Stigler argue “the field can appear, from a big-picture perspective, to be accumulating random facts and unverified observations.” Arguing that “knowledge will accumulate only within programs” these scholars call for “a relatively small (smaller than the number that exist now) programs for the field, as a whole, to show steady progress” (Chap. 10, p. 284).

In agreement with Hiebert and Stigler (this volume), and adopting Vieluf and Klieme’s (this volume) use of the term paradigm, we propose that another possible starting point would be identifying a small group of paradigms. This might not be easy, especially nowadays, given that the boundaries between different paradigms may not be easy to demarcate. But, mapping the field in terms of the existence of certain paradigms [e.g., by drawing on Shulman’s (1986) approach back in 1980s] appears to be a particularly worthwhile first endeavor and one which, to the best of our knowledge, has not been recently attempted. Scholars could also be asked to nominate existing paradigms and then, through consensus, a list of the most important ones could be developed. This should not only facilitate the next steps in theorizing teaching but should also give a clearer structure and organizational framework to the existing literature.

  • Step 2

Having selected a paradigm to work in, we believe that is of paramount importance to agree, before moving forward, on the value and implications of cumulative work. When we began this project, we assumed that the authors’ acceptance of our invitation implied a shared understanding of why such an exercise was important. We later realized that this was not entirely true. In hindsight we recognize that ensuring some common ground about the value and implications of cumulative work is a fundamental prerequisite for making the theorizing of teaching more collaborative.

  • Step 3

Within paradigms, the process of theorizing teaching can evolve in multiple directions three of which we outline below. The first is having meta-theoretical discussions on the purposes and functions a theory needs to serve. Without such discussions, as Biesta suggests, the existing differences might appear inexplicable and insurmountable. Hill and Lampert also stress the key role that such discussions can have when they present David Cohen in their foreword asking Heather Hill, “Why would you want to develop a theory of teaching?” (p. 190). Such meta-theoretical discussions were not planned for this volume because we assumed that contributors generally had similar views on these issues. The Delphi study made us realize the importance of discussing these issues early on.

A second is attempting to reach consensus on the definitions and attributes of theories, as well as on the extent to which theories could or should accommodate different aspects of context and content. This can yield important insights, even when disagreements emerge, since it can reveal issues, ranging from underlying substantive theoretical differences about the purpose of theorizing teaching that need to be discussed to more minor linguistic differences that need to be clarified.

A third and perhaps the most critical direction is identifying the most important theories within each paradigm and exploring how they can be synthesized locally [to use Bikner-Ahsbahs and Prediger’s (2010) words] in ways that would help to better describe and explain teaching. During this process, it could be interesting to pursue Herbst and Chazan’s idea to have theories openly compete with each other (see more on that in Chap. 10).

  • Step 4

Regardless of how critical work within any given paradigm can be, it might be limiting and limited if it is not informed by the perspectives of other paradigms. Thus although we propose that work be undertaken within homogeneous groups subscribing to the same paradigm in the third step, we also believe that there is great value in conferring with other paradigms. This volume shows that different perspectives can enrich each other. Notice, for example, how Biesta’s objections to causality (see Chap. 10) might problematize and enrich the discussions undertaken within the Teaching Effectiveness Research paradigm, or take Vieluf and Klieme’s chapter (this volume) in which they discuss how the latter paradigm and the Practice Theories paradigm can inform each other. We would like to propose that after working within paradigms, such heterogeneity be purposefully incorporated into the work of more homogenous groups by inviting critical friends that represent other perspectives. This will not be to reach a consensus, as we learned in this volume, but it can help identify blind spots and limitations, enrich ideas, and point towards next steps that can be undertaken within a given paradigm.

  • Step 5

A final, yet, equally important, step pertains to communicating all this work, both within and across paradigms, in a clear, useful, and usable way that would contribute toward its development in the future by enticing the next generation of researchers to engage in the cognitively demanding work of theorizing teaching. We recognize that often journal space restrictions are limiting. Edited volumes like this one, as well as other events and organizations (symposia in conferences, forming special interest groups, etc.) might offer additional ways of communicating the results of such work in comprehensible ways and in the level of detail required. We hope that in this volume we have clearly communicated the process and results of this exercise and so can provide an example for others to follow or develop on.

9 Limitations of the Approach Taken

The approach we have taken yields a significant delineation of the current status of theorizing teaching and provides many interesting ideas for future work in this field. It does, however, have several limitations.

The core of the project was the contribution of a group of eminent researchers who were invited to participate. The concrete focus on researchers following an instrumental idea of teaching was based on our own background and expertise. Following the approach suggested by Bikner-Ahsbahs and Prediger (2010), we selected researchers whose work had some areas of overlap and included a few additional perspectives for enrichment. This resulted in certain ideas being highlighted and other important areas of teaching, such as issues raised by critical race theory (e.g., Howard & Navarro, 2016; Ladson-Billings & Tate, 1995; Ledesma & CalderĂłn, 2015), ecological theories (e.g., Bronfenbrenner, 1989), relational and affective teaching (e.g., Grossman et al., 2009; Lampert, 2001; Noddings, 2001), sociocultural (e.g., Banks & Banks, 2004; Gallego et al., 2001; Gay, 2018) and sociopolitical (e.g., Nasir et al., 2016; Nieto, 2005) contexts, as well as historical perspectives (e.g., Kafka, 2016; Sweeting, 2005) not being addressed or addressed only in single chapters. Ideas such as the interdependency of teachers and students and the consideration of the influence of systems and structures on teaching had originally been expected to be better represented in the book based on the chapter by David Cohen; his unexpected passing away resulted in their underrepresentation. It is obvious that no single book can address all of the aspects relevant to theorizing teaching and that our decision to ensure there were sufficient overlaps between chapters to enable a productive exchange between the authors led to a further narrowing of focus. Future research should follow a similar procedure, but with different foci, so that a more complete picture of the field of theorizing teaching could emerge.

To ensure comparability across the chapters, we asked all of the authors to respond to five questions derived from a review of the literature review (Chap. 1). Different, or differently phrased questions could have resulted in different insights into research on teaching. The authors also each chose to concentrate on some questions more than others in their responses.

The structure of the Delphi study is also likely to have had an impact on the results (Chap. 10). The contributions were summarized in a series of statements, and this was followed by a member-check phase to ensure that authors agreed with the summaries of their work. The length of the responses was also limited. The summaries were necessary to ensure a manageable work load, but some misunderstandings may have arisen from the resulting reduced context. Also, to again reduce the work load, we asked the authors to only provide a comment on the statements with which they most agreed or disagreed, which meant we did not have a response to every statement from everyone. We also restricted the exchange between authors to one round, whereas several additional rounds, ideally not only in written form, but also in symposia or a conference environment, would have been very interesting, if also likely too demanding of participants’ time.

Despite these limitations, we are convinced that the approach we have used has provided a wealth of important insights into theories of teaching and a great starting point for future discussions in this area.

10 Conclusion

This book was quite an ambitious and complex endeavour. We wanted to provide an up-to-date overview of the theorizing of teaching that included a review of the literature, the views of leading experts in the field, and a directed discussion among the experts on specific aspects of theorizing teaching. We believe that many insightful and thought-provoking ideas are collected in this book and that it provides a unique view on the subject. The key ideas to emerge from the compilation of this endeavour are: The issue of theories of teaching is highly complex; theories and their development, which we tried to separate using five guiding questions, are quite intertwined; the lines between attributes of theories, the process of generating them, and whether and how to develop more comprehensive theories of teaching in the future, are hard to distinguish. It became evident that the purpose and definition of theories of teaching provide essential basis for the other issues. Because the authors differed in their definitions and the purposes that they ascribed to theories of teaching, they were often not focusing on the same aspects of the complex phenomenon of teaching.

Despite these challenges, many important issues were raised and addressed such as the question of how to define theory as well as teaching, the necessity of reflecting on the purpose of theories, what to include in a theory and what not, the different levels at which theories can be developed, the role of content specificity and context sensitivity in developing such theories, the embeddedness of theories in different paradigms, the role of teachers with respect to theories of teaching and related to that the link between research and practice, and how to come up with a useful consensus-development process.

So where are we in terms of theorizing teaching? There has been considerable progress in theorizing teaching since the publication of the work in our literature review (Chap. 1); however, this volume demonstrates that there is still much work to be done. The big disagreements between the authors highlighted the complexity in research on teaching and revealed that we need more close collaborations in order to clarify these issues, taking an explicitly stronger meta-level stance in discussions about theorizing teaching, along the lines of those in this book. More specifically, each research group needs to be more explicit in their own work with respect to terminology and the paradigm they follow, including its underlying assumptions. It would be very useful to continue comparing different approaches and theories in order to identify similarities and differences. Based on such work, a meta-framework could be developed that helps to organize different theories into an overarching picture to see how existing theories of teaching relate to each other and on which levels they are located. This would also give us better ways to discuss whether and to what degree consensus could and should be reached about certain aspects of theories. Such a meta-framework could be started within paradigms before being extended to discussions across paradigms.

We have learnt a great deal about the opportunities and constraints of such a complex endeavour and have used the exercise to develop several ideas on how to continue and optimize such exchanges in the future. Fortunately, there is already some interest from the contributors for continuing these fruitful discussions. We are looking forward to it, hoping that the readers of this book will also be interested in joining such efforts. For now, we want to conclude with an adapted version of the quote that has been ascribed to Kurt Lewin: There is nothing as practical as theory—but also nothing as complex as theory and theorizing.