The Theoretical and Empirical Basis of Teacher Leadership

The Need to Continue to Explore Teacher Leadership in Ways Similar to York-Barr and Duke

Little (2003) noted that starting in the 1980s—the beginning of York-Barr and Duke’s (2004) review timeline—schooling went through three distinct phases that shaped how teacher leadership was viewed, from “leadership rooted in specific teaching contexts and small-scale collaboration” (p. 405), to teacher leadership being an integral part of whole-school reform in the late 1980s to early 1990s, to teacher leadership most recently supporting accountability mechanisms in the early 2000s. More specifically, the creation of teacher leaders in the last decade has been

driven . . . by the urgent need for expertise to expand instructional capacity within schools. School officials seeking to substantially increase students’ performance on annual assessments have appointed teachers to serve as instructional coaches, curriculum writers, professional developers, and data analysts. (Donaldson et al., 2005, p. 1090)

In this way, as the call for accountability has grown, so has the population of teacher leaders supporting accountability-related initiatives and programs. Given the evolution of how teacher leaders were viewed and utilized within schools during these two decades, York-Barr and Duke (2004) largely sought to unify ideas about teacher leadership with the aim of guiding future research. However, as teacher leadership did not become part of the accountability mechanism until the early 2000s, we believed this context and the accompanying issues were only partially accounted for by York-Barr and Duke (i.e., 2000–2004). Consequently, due to this shift in the educational climate, we believed that many of the issues that constituted teacher leadership explored by York-Barr and Duke (e.g., how teacher leadership is defined, what teacher leaders do, who teacher leaders are, and the conditions that influence teacher leadership) may have undergone substantive transformations, especially given the changing activity within which teacher leadership is situated. As such, many of the questions York-Barr and Duke explored were reconsidered in this current literature review.

The Need to Move Beyond Exploring Teacher Leadership in Ways Similar to York-Barr and Duke

Not only did we investigate teacher leadership potentially shaped by accountability mechanisms and other emerging forces pressing on the ecology of teacher leadership, we also looked at teacher leadership as constituted in different disciplines, the ways in which it was framed by theory, and the roles social justice and issues of equity played in the work of teacher leaders. Concerning the constitution of teacher leadership in disciplinary contexts, Spillane and Hopkins (2013) asserted that researchers “must take the school subject into consideration because instruction is not a generic or monolithic variable but rather a subject specific one” (p. 722, italics in original). They continued to say that subject matter not only shapes teachers’ instruction but also their responses to reforming their practice in those subjects as well. Subject matter is, in fact, so influential in the ways in which teachers and schools behave that Ball and Lacey (2012) went as far as categorizing different subject areas as subcultures. In terms of leadership, Spillane, Diamond, and Jita (2003) noted in their study that the number and type of leaders varied depending on the subject. For example, math and literacy was typically led by several people and spread between administrators and teachers with formal leadership designations, whereas science was typically led by a few informal teacher leaders. Given these differences, we felt it was important to explore the empirical research related to teacher leadership in particular subject areas and to specifically investigate whether or not teacher leadership was discussed and perhaps conceptualized differently across the various disciplines.

York-Barr and Duke’s (2004) characterization of the literature on teacher leadership as “largely atheoretical” (p. 291) prompted another area of inquiry in this literature review. Because of their disturbing findings, we wanted to examine the extent to which this characterization remained true today. Additionally, we endeavored to assess whether researchers took up York-Barr and Duke’s conceptual framework for teacher leadership or if there were other theories informing teacher leadership. York-Barr and Duke stated, “Research grounded in theory is less likely to revisit what is already known and is more likely to further existing understandings and inform practice” (p. 291). It was our hope that in the span of a decade, researchers had taken this notion to heart and attempted to further understandings about teacher leadership by using robust theory to inform their research.

A final area we wanted to investigate via this literature review was that of social justice and issues of equity in terms of teacher leadership. We were not only interested in research that attended to these issues in terms of the teacher leaders themselves but also in terms of teacher leaders preparing to lead in diverse settings and on topics related to social justice. As schools become increasingly diverse, both with regard to the student population as well as the teacher population, researchers need to explore the ramifications of these changes. For example, Madsen and Mabokela (2014) noted that tensions can exist among a diverse group of teachers. Certainly these tensions could affect the ways in which teacher leaders are identified, developed, treated, and the work they are able to do within a school. Terrell and Lindsey (2008) have advocated for a special type of leadership they call culturally proficient leadership in which one must understand his/her own cultural assumptions in order to lead effectively in diverse settings. Perhaps skills found in this type of leadership were being integrated into teacher leader training in order to produce culturally sensitive leaders. With the changing landscape of schools, we felt we would be remiss in ignoring social justice and issues of equity.

Collectively, the decisions made pursued questions that extended those findings of York-Barr and Duke, as well as asked additional justified and needed questions. Like others (Curtis, 2013; Leithwood et al., 2004; Muijs & Harris, 2003, 2006), we saw teacher leaders as potentially among the most influential leaders in schools. As such, this review is a critical vehicle for, among other things, reifying teacher leaders’ roles in schools, how teacher leadership is conceptualized and framed, and how teacher leaders can support all learners. But first, providing our conceptualization of teacher leadership will shed further light on the decisions we made regarding the literature reviewed in this current research.

Inclusion and Exclusion Criteria

The inclusion/exclusion criteria for the studies in our literature review were inspired by both conceptual and pragmatic considerations. More specifically, because York-Barr and Duke (2004) found that most of the literature they reviewed was solely descriptive and limited to case study designs, small sample sizes, and self-report or interview methodologies, their criticism and suggestions formed the foundation for our inclusion criteria (i.e., empirical/beyond purely descriptive, small sample sizes [N ≥ 5], triangulated data). We then created criteria based on our working definition of teacher leaders (i.e., K–12 teachers, classroom responsibility, lead the school). Finally, we created practical criteria that would allow us to uncover high-quality empirical research that truly focused on teacher leadership (i.e., only teacher leaders, peer reviewed, teacher leadership central to research). More details about each of the inclusion and exclusion criteria are found in Table 1.

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Table 1

Criteria and impetus for criteria for inclusion/exclusion in literature review

Source of criteria impetus	Criteria impetus	Resulting exclusion criteria
York-Barr and Duke (2004)	Much of the literature was purely descriptive	Exclude purely descriptive/argument/rationale pieces; literature must report the findings of empirical studies
	Small sample sizes, single case study designs	Exclude studies where N < 5
	Much of the literature was solely self-report	Exclude studies in which data is untriangulated
Conceptual framework on teacher leadership	Teacher leaders are K–12 teachers	Exclude studies in which the participants are college-level teacher leaders or preservice teachers
	Teacher leaders maintain classroom responsibilities	Exclude studies in which participants are no longer in the classroom (e.g., district specialists, coaches with no teaching responsibilities)
	Teacher leaders should lead the school	Exclude studies in which teacher leadership is to promote a particular program/curriculum
Pragmatic considerations	Teacher leadership is a unique type of leadership	Exclude studies in which teacher leaders are participants, but part of a larger leadership group
	High-quality research is peer reviewed	Exclude studies without peer review (e.g., online submissions, reports from centers/organizations). Exception: dissertations, which are often subject to rigorous committee review
	Teacher leadership is the focus of the study	Exclude studies in which teacher leadership is peripherally included

Search and Abstract Review Methods

To search for literature, we used the Education Research Complete database. Using the search parameters of “teacher leadership” in any field and constraining the search to January 2004 through December 2013, our search yielded 704 results. We acknowledge that research meeting our criteria has been published since December of 2013; however, we began this research in 2014 and the large scope of this research necessitated a clear cutoff date. Consequently, we chose to end our literature collection with items published through December of 2013. In order to ensure consistency during the abstract review process, we began by reviewing 10 abstracts independently and applying the criteria found in Table 1 to those abstracts. We then met to discuss our findings and resolved all interpretive discrepancies. We repeated this process twice more, once with 20 abstracts, and then with 40 abstracts.

After reviewing a total 70 abstracts, we then reviewed the remaining 634 abstracts independently. If we did not feel we had enough information in the abstract to apply our criteria, we obtained a copy of the piece of literature for further review. Similarly, edited books were obtained so each chapter could be independently reviewed. Of the 704 abstracts reviewed, 75 pieces of literature were excluded immediately from our review because although they were somehow related to the search term, teacher leadership was only peripherally connected to the research; this brought the total to 629 total pieces of literature focused on the topic of teacher leadership. Five hundred and fifty-seven more pieces of literature were then excluded from our review because they did not meet one or more of our criteria. Thus, based on the abstracts reviewed, 72 pieces of literature (approximately 10%) were included for full review.

To begin our in-depth reading and review of the 72 pieces of literature, we created a shared spreadsheet that would allow us to chronicle our findings and questions about the literature. In this document, we recorded basic bibliographic information, methodological details, data that would help us answer our research questions, and other interesting topics that arose as we conducted our review (e.g., whether or not authors explicitly provided their definition of teacher leadership). Independently, we reviewed the same eight pieces of literature (approximately 10%). We then met to discuss our findings, record data in the spreadsheet, and resolve all interpretive discrepancies. We then reviewed the remaining 64 pieces of literature independently, meeting weekly to discuss any further questions or issues. During this process, all articles were annotated and placed in an archive so that each of the facets of teacher leadership of interest was traceable back to the original text. If disagreements or questions arose about a specific article, the researchers revisited the original archived article and sought consensus of interpretation before finalizing the analysis result for the perspective article.

As we completed this more in-depth analysis of each of the 72 pieces of literature, we found that 18 pieces we initially included after reading the abstracts were not appropriate for this review. The most common reason for exclusion was that on further investigation, teacher leadership was merely peripheral to the article’s focus. For example, Booth’s (2012) article focused more on the online learning communities themselves rather than the teacher leaders in those communities. After excluding these additional 18 pieces, we had 54 pieces of literature on which to base this literature review. Figure 1 contains a flow chart describing how the literature was narrowed to the 54 pieces finally included for this literature review. Figure 2 provides further details concerning the number of pieces excluded by criteria item.

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Figure 1.

Inclusion/exclusion process for literature review.

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Figure 2.

Pieces excluded from literature review by criteria (n = 650).

How Is Teacher Leadership Defined and What Are the Constructs/Elements of Teacher Leadership Within the Conceptualization?

As we were documenting our findings for this research question, we were struck by how few authors explicitly described their particular definition of teacher leadership. Many pieces of literature (n = 35; 65%) simply listed others’ definitions of teacher leadership or noted that there is often confusion surrounding the definition, but never definitively stated how they defined teacher leadership for the purposes of their study. For example, Brosky (2011, p. 3) stated,

In the field of education, a struggle continues with the basic definition of teacher leadership that should be fundamental in educators’ professional vocabulary. Many administrators, boards of education, parents, and even teachers don’t recognize or understand teacher leadership. This lack of understanding adds to the obstacles teacher leaders face (Ackerman & Mackenzie, 2006; Donaldson, 2007). Katzenmeyer and Moller (2001) contend, “We are a long way from a common understanding of teacher leadership. Confusion about definitions and expectations of teacher leaders abound” (pp. 4–5). York-Barr and Duke’s (2004) meta-analysis on 20 years of research on teacher leadership states, “The lack of definition may be due, in part, to the expansive territory encompassed under the umbrella term ‘teacher leadership.’” (p. 260)

Albeit prudent to note there is widespread confusion concerning what teacher leadership is, we sought to answer how researchers in the field defined teacher leadership, at least in terms of their research. As such, the remainder of the findings surrounding this research question focus on the 19 pieces of literature (35%) that, to varying degrees, explicitly described what they believed teacher leadership to be. Many authors chose to cite another scholar’s definition of teacher leadership, as in the case of Carpenter and Sherretz (2012, p. 91) when they stated,

To guide the current study we perceive teacher leadership as conceptualized by Childs-Bowen, Moeller, and Scrivener (2000): “We believe teachers are leaders when they function in professional learning communities to affect student learning; contribute to school improvement; inspire excellence in practice; and empower stakeholders to participate in educational improvement.” (p. 28)

Other authors, such as Taylor, Goeke, Klein, Onore, and Geist (2011), defined teacher leadership themselves, and noted that for their study, “Our commitment was to a definition of TL [teacher leadership] based in the work of classroom teachers that was neither supervisory nor hierarchical but focused on individual and school growth and development” (p. 920). Regardless of the methods of defining teacher leadership, we extracted these definitions and found that there were five general themes that described teacher leadership, italicized and described next.

The first theme was teacher leadership goes beyond the classroom walls. Several authors opined that to be a teacher leader one must lead more than one’s students and conduct leadership work outside of one’s classroom (Chamberland, 2009; Chesson, 2011; Durias, 2010; Gonzales, 2004; Hunzicker, 2012; Vernon-Dotson, 2008). The second and third themes described what teacher leaders should be doing beyond their classroom walls. Many scholars believed that teacher leaders should support professional learning in their schools, which could be in the form of leading professional learning communities, conducting formal PD, or assisting other teachers in classrooms (Can, 2009; Durias, 2010; Gonzales, 2004; Gordin, 2010; Margolis, 2012; Margolis & Doring, 2012; Margolis & Huggins, 2012; Muijs & Harris, 2006; Vernon-Dotson, 2008; Vernon-Dotson & Floyd, 2012).

Additionally, several authors asserted that teacher leaders should be involved in policy and/or decision making at some level (Can, 2009; Carpenter & Sherretz, 2012; Durias, 2010; Gonzales, 2004; Vernon-Dotson, 2008). A fourth major theme that arose from the definitions of teacher leadership was that the ultimate goal of teacher leadership is improving student learning and success (Carpenter & Sherretz, 2012; Hanuscin, Rebello, & Sinha, 2012; Hunzicker, 2012; Vernon-Dotson & Floyd, 2012). Finally, many definitions seemed to point to teacher leaders working toward improvement and change for the whole school organization (Carpenter & Sherretz, 2012; Gaffney & Faragher, 2010; Gigante & Firestone, 2008; Taylor et al., 2011; Vernon-Dotson & Floyd, 2012).

To What Extent and in What Ways Is Teacher Leadership Being Investigated Within the Different Disciplinary Contexts?

Fifteen (28%) of the 54 pieces of literature focused on teacher leadership within specific disciplinary contexts. Literacy/English was the most common discipline found in the teacher leadership literature (six focused solely on literacy/English and one other focused on literacy/English and math). However, science was also a significant area of focus, with three pieces of literature focusing solely on science, and two more focusing on math and science/STEM. Although it was our intention to draw comparisons between the pieces of literature in our review and the findings of Spillane et al. (2003) that there are differences in the number and types of leaders depending on the discipline context, this sample size is much too small for us to draw conclusions on this matter. With only seven pieces of literature focused on literacy/English, five pieces focused on science, and four focused on math, any trends would be difficult to discern (see Table 2 for details). Moreover, it should be noted that whereas these pieces of literature were rooted in these disciplines, in most pieces of literature the discipline did not seem to play a large role in the research at hand. Rather, whether the study took place within the realms of literacy, math, or science was by and large found to be extraneous contextual information.

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Table 2

Discipline contexts found in literature review

Subject/discipline	Authors
Agricultural education	Westfall-Rudd (2011)
English language learners	Baecher (2012); Chamberland (2009)
Literacy/english	Edge and Mylopoulos (2008); Friedman (2011); Gaffney and Faragher (2010); Margolis and Deuel (2009); Yonezawa, Jones, and Singer (2011)
Math	Durias (2010)
Math and literacy/English	Hoang (2008)
Math and science/STEM	Gigante and Firestone (2008); Hunzicker (2012)
Science	Hofstein, Carmeli, and Shore (2004); Singh, Yager, Yutakom, Yager, and Ali (2012); Hanuscin, Rebello, and Sinha (2012)
Vocational education	Adams and Gamage (2008)

What Theories Are Used to Frame Research Surrounding Teacher Leadership?

Given that York-Barr and Duke (2004) found the literature on teacher leadership to be “largely atheoretical” (p. 291) as well as the fact that they developed a theory of action for teacher leadership that included the foundation on which teacher leadership may happen, we explored the use of theory in our review. Of the 54 pieces of literature, 33 pieces (61%) specifically cited at least one theory that informed the work. It should be noted that there were other researchers who mentioned theory, but after careful review were judged to have not used the theory to inform their work. Rather, theory was mentioned in passing, or in the literature review as something that others had used to frame research surrounding the topic at hand. The most popular theory cited by far was distributed leadership, with 10 pieces of literature (19%) using this theory to inform the research. Other notable theories used to frame research in teacher leadership include democratic/constructivist leadership, structure and agency, parallel leadership, transactional leadership, and communities of practice (see Table 3). As far as taking up York-Barr and Duke’s theory of action for teacher leadership, only one piece of literature (Fairman & Mackenzie, 2012) used this theory to frame their research.

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Table 3

Theories cited in literature

Theory	Authors
Bandura’s Social Cognitive Theory	Friedman (2011)
Bethune’s Founding Principles	Watson (2007)
Boundary Crossing	Pegg (2010)
Contemporary Planning Theory for Adult and Continuing Education	Westfall-Rudd (2011)
Democratic/Constructivist Leadership	Shiu, Chrispeels, and Doerr (2004); Gonzales (2004)
Distributed Leadership	Anderson (2012); Chamberland (2009); Gigante and Firestone (2008); Grant (2009); Hands (2012); Harris and Townsend (2007); Hoang (2008); Muijs and Harris (2006); Supovitz (2008); Vernon-Dotson and Floyd (2012)
Ecological Policy Analysis	Margolis (2012)
Friere’s Theory of Critical Consciousness	Bradley-Levine (2012)
Giddens’ Structure and Agency	Hoang (2008)
Gordon’s Model of Instructional Leadership	Margolis and Huggins (2012)
Lave and Wenger’s Sociocultural Teacher Learning Models	Margolis and Doring (2012)
Mental Models	Shiu et al. (2004)
Micropolitical Theory	Brosky (2011)
New Cultural Theory	Scribner and Bradley-Levine (2010)
Organizational Leadership Theory	Scribner and Bradley-Levine (2010)
Organizational Role Theory	Gordin (2010)
Parallel Leadership	Chew and Andrews (2010)
Resilience	Yonezawa et al. (2011)
Sensemaking in Cognition	Hoang (2008)
Social Networks	Margolis (2012)
Teacher Subject-Matter Knowledge	Hoang (2008)
Theories of Power	Anderson (2012); Podjasek (2009)
Transformational/Transactional Leadership	Adams and Gamage (2008); Robinson (2009); Siers and Gong (2012)
Wenger’s Communities of Practice	Edge and Mylopoulos (2008)
York-Barr and Duke’s Dimensions of Practice	Hanuscin et al. (2012)
York-Barr and Duke’s Teacher Leadership for Student Learning	Fairman and Mackenzie (2012)

Note. Many authors (e.g., Margolis, 2012; Scribner & Bradley-Levine, 2010) used multiple theories to inform their work.

How Are Teacher Leaders Prepared and What Elements Appear to Be the Most Fruitful for Developing Teacher Leaders?

Based on the literature, teacher leaders are largely being prepared in two ways, either via PD/local training/conferences or via university Master’s programs. Within these two major teacher leader preparation categories, we found themes among the components that constituted these types of preparation. Given that only nine pieces of literature (17%) discussed teacher leader preparation in detail, we cannot make any judgments about the fruitfulness of any of these particular components or programs. However, each of the nine pieces of literature did have positive evaluations of these programs, which could imply that the themes/components we will present hold promise for effective teacher leader preparation.

Seven pieces (13%) of literature discussed teacher leader preparation taking place via PD, conferences, and local training programs. There was a great deal of variation in the duration and number of occasions for this preparation, ranging from weeklong trainings (Borchers, 2009) to trainings held over several years (Hanuscin et al., 2012; Shiu et al., 2004; Vernon-Dotson, 2008). More consistent were the components found within these types of trainings. Five out of the seven preparation programs included training in pedagogical skills and strategies (e.g., Durias, 2010; Edge & Mylopoulos, 2008; Hofstein et al., 2004). Six out of the seven preparation programs included some type of training in content knowledge or a particular curriculum (e.g., Borchers, 2009; Hanuscin et al., 2012; Vernon-Dotson, 2008). Finally, all seven preparation programs that took place via PD, conferences, and local training included training in leadership skills and strategies. Hofstein et al. (2004) asserted that in the past, leadership skills were often neglected in PD presented to those who were expected to lead their schools. As such, 30% of their PD program for teacher leadership in chemistry consisted of training on content knowledge, 45% on pedagogical content knowledge, and 25% on leadership abilities. Beyond Hofstein et al., several other researchers seemed to follow in their footsteps and strive for this type of integrated teacher leader preparation.

Only two pieces of literature (4%) reported preparing teacher leaders via university master’s programs with a level of detail that allowed us to understand the components of the programs. Hunzicker (2012) described a STEM Master’s program that contained a course in teacher leadership, and Taylor et al. (2011) conducted research surrounding an entire Master’s program in teacher leadership. Examining these two pieces of literature, we found that the teacher leadership components of these programs had two commonalities. First, they both seemed to focus on personal and professional growth. In the teacher leadership course within the STEM Master’s program, students had to create a portfolio targeting engagement in self-assessment and reflection, and were required to compile artifacts that illustrated professional growth. A large component of Taylor et al.’s teacher leadership program was action research; students were to engage in inquiry and take steps to improve their practice. Additionally, both Hunzicker and Taylor et al. noted that these programs allowed for a great deal of personalized learning.

As Taylor et al. (2011) contended,

If teacher leaders are told what to learn, how to learn, and why to learn, their learning is controlled by others and their capacity to lead is stunted. To learn to lead, then, teachers must place their own issues and concerns at the center of their learning process, know themselves as learners, reflect on their learning and share it with others. (p. 922)

Ultimately, what was evident with respect to teacher leader preparation was that two types of preparation were found (i.e., PD and university programs), with PD being more common.

What Are the Effects of Teacher Leadership?

Regarding the effects of teacher leadership, York-Barr and Duke (2004) observed, “The literature is relatively rich with claims of the potential and desired effects of teacher leadership and relatively sparse with evidence of such effects, especially at the levels of classroom practice and student learning” (p. 282). We find this observation to hold true today. None of the literature in our review focused on this topic. Rather, the effects of teacher leadership were limited to the effects on the teacher leaders themselves and the colleagues of these teacher leaders.

What Factors Facilitate or Inhibit Teacher Leadership?

As seen above, there are several benefits to teacher leadership. Consequently, it behooves us to better understand what enables and constrains teacher leadership. Concerning factors that support teacher leadership, four general themes in the literature were identified: external training and support for teacher leaders, support from administration, climate and structural factors that better allow teacher leaders to do their work, and clear-cut job responsibilities and recognition for meeting those responsibilities.

In What Ways Does the Research Surrounding Teacher Leadership Examine Issues of Diversity and Equity?

Of the 54 pieces of literature in our review, only five (9%) focused on issues of diversity and equity. Bradley-Levine (2012) and Larrabee and Morehead (2010) conducted research in graduate-level courses that were preparing teacher leaders. The program Bradley-Levine (2012) explored was centered on the concept of critical consciousness and sought to prepare teacher leaders to become “moral and transformative agents committed to the principles of equity, justice, and diversity” (pp. 751–752). As such, the research conducted sought to evaluate the effectiveness of the program in instilling critical consciousness. Larrabee and Morehead (2010) focused on one particular course within a graduate program and the students’ reflections on a lecture given on the topic of lesbian, gay, and bisexual issues.

Durias (2010), Podjasek (2009), and Watson (2007) all conducted research on teacher leaders in the field and focused on particular minority groups. Durias (2010) investigated the motivations and practices that encouraged or hindered math teacher leaders of color to take on larger leadership roles. Podjasek (2009) examined the experiences of female elementary teacher leaders and their perceptions of leadership. Finally, Watson (2007) sought to understand why female African American teacher leaders were inspired to pursue higher leadership positions within urban schools. Despite each of these topics being worthy of exploration, given the current educational, social, and political contexts, it was surprising these were the only issues surrounding equity and diversity found in this collection of literature.

Teacher Leadership in Schools Today and the Preparation for These Roles

This first discussion theme focuses on a consideration of what this collection of literature says about what we believe teacher leadership to be in the current climate and organization of schools. These beliefs were manifested in how researchers defined teacher leadership. In our Results section, relatively few researchers (n = 19; 35%) explicitly described how they defined teacher leadership for the purposes of their study. This finding was judged to be problematic, as it reveals that a majority (n = 35; 65%) of the research reviewed did not definitively state what they believed teacher leadership to be. Instead, many researchers mentioned several other researchers’ definitions of teacher leadership in passing, but in the end did not indicate how they were defining teacher leadership within their studies. In those instances within the literature in which researchers did define teacher leadership for their study, it was conceptualized as working beyond the classroom walls, supporting professional learning in their schools, and being involved in policymaking and decision making at some level with the ultimate goal of improving student learning and success and seeking improvement and change for the whole school organization.

One implication of the lack of clarity surrounding teacher leadership is that it then becomes conceptually ill defined, like inquiry or standards-based teaching (Windschitl, Thompson, Braaten, & Stroupe, 2012). And like inquiry or standards-based teaching, this muddiness could lead to inconsistencies between the research literature on teacher leadership and local enactments of teacher leadership. As an example, Beachum and Dentith (2004) did not explicitly define teacher leadership for their study, but rather seemed to cite the body of literature on teacher leadership in general by stating that teacher leadership is “leadership beyond traditional classroom boundaries” (p. 277). In this definition, it is implied that teachers are still in the classroom, but still, this definition is quite vague in what exactly teacher leadership means for their study. Beachum and Dentith’s research identified how teacher leadership led to the establishment of a positive culture in the school because teachers felt empowered. Given these findings, if a school strove to enact teacher leadership as informed by Beachum and Dentith’s work, but their teacher leaders did not maintain K–12 classroom-based teaching responsibilities, the positive culture and feeling of teacher empowerment sought may not be among the eventual outcomes.

This is an entirely plausible alternative outcome because, as Mangin and Stoelinga (2008) have noted, teacher leaders with classroom responsibilities are afforded an understanding of the complexities of teaching. Additionally, Curtis (2013) and Muijs and Harris (2003, 2006) have stated how teacher leaders with classroom teaching responsibilities are uniquely positioned as collaborators with a capacity for modeling and refining content-specific instructional practices. This example is one illustration of how the lack of clarity in how teacher leadership is defined might lead a mismatch between research and practice.

Related to the threat of inconsistency between local enactments of teacher leadership and teacher leadership research, the lack of clarity surrounding teacher leadership holds the potential to inhibit the field from building on others’ work. That is, if researchers are, as Neumerski (2012) described, using teacher leadership as an “umbrella term referring to a myriad of work” (p. 320), it becomes difficult to closely examine consistent facets of teacher leadership in order to construct reliable knowledge. Put more concisely, if researchers are not explicit in articulating how they are defining teacher leadership or the specific roles teacher leaders in their research do or do not take on, it seems unlikely that consistent evidence can be collected to ground knowledge claims about teacher leadership or that connections will be made between the current climate or organization of schools and teacher leadership.

In considering teacher leadership in the current climate and organization of schools, consideration was given to the ways in which the research surrounding teacher leadership investigated issues of equity and diversity. This important component of teacher leadership was highlighted because of the influence equity and diversity can have in determining which teachers take on leadership roles and how teacher leaders more generally, once taking these roles, support the diverse populations of teachers and students they lead. To prepare teacher leaders to lead in an equitable manner, especially as diverse populations come together in ways that might lead to unequal power distributed among populations or groups, researchers like Bradley-Levine (2012) have considered frameworks like Freire’s (1970/2006, 1973/2002) critical consciousness. As teacher leaders develop critical consciousness, they carefully give consideration to the problems related to diversity and equity within schools and society more broadly by considering the roles historical and social activity had in creating these problems.

Moreover, this critical consciousness is wed with a balance of action (hooks, 1994), whereby teacher leaders take action to provide equitable educational opportunities for all students. In this review of teacher leadership, equity and diversity was seen as being central to identifying and preparing teacher leaders. However, as noted in the results, only five (9%) of the articles reviewed attended to issues of diversity and equity. To reiterate, this meant that equity and diversity were not considered in 91% (n = 49) of the articles included. Given the rapidly changing world of education as well as the populations found in schools, this manifests as an unacceptable oversight. Those five pieces of literature that did attend to issues of equity and diversity provided insight into possibilities for preparing teacher leaders (e.g., Bradley-Levine, 2012; Larrabee & Morehead, 2010) or the experiences of teacher leaders from minority groups (i.e., Durias, 2010; Podjasek, 2009; Watson, 2007), but these few studies hardly provide the strong base of literature.

When considering teacher leadership preparation more broadly beyond considerations of equity and diversity, more research was identified. However, only nine pieces of literature (17%) discussed teacher leader preparation in detail. Additionally, these nine pieces of literature examined widely varied programs or components of teacher leadership preparation, from teacher leader preparation taking place via PD, conferences, and local training programs, to university master’s programs and courses. Because of this lack of focus related to teacher leadership preparation, we decline to make judgments about the importance or promise of any one program or components of these programs. However, even across these varied organizational structures within which teacher leaders were supported, it was noted that there was relative agreement in the three areas of learning (content knowledge, pedagogical knowledge, leadership skills) that should have been be emphasized within a teacher leadership preparation program.

In summary, it seems imperative that future research on teacher leadership clearly defines the concept of teacher leadership, even while acknowledging disagreement and ambiguity within the field and variation in localized organizational structures. It is only through conducting research using these working definitions that the notion of teacher leadership will be clearly defined. Furthermore, these findings suggest that those working in teacher leadership programs (university-based or school-based) should conduct empirical research on the components as well as the outcomes of these programs. Additionally, we encourage teacher leader preparation programs to discuss best practices related to issues of equity and diversity.

Contexts and Theories That Frame Research Surrounding Teacher Leadership

As stated earlier, this literature review sought to better understand the emerging forces potentially pressing on the ecology of teacher leadership. In considering this, researchers like Spillane and Hopkins (2013), Ball and Lacey (2012), and Spillane et al. (2003) have revealed how disciplinary context (e.g., science, mathematics) is likely one of the key contextual factors that might shape teacher leadership, especially because the disciplinary contexts have been characterized as, among other things, subcultures (Ball & Lacey, 2012). Consequently, we explored whether our review of the literature might allow us to aggregate research on teacher leadership by discipline such that the unique idiosyncrasies of each discipline could be illuminated. However, as noted in our results, the small number of studies from each of the disciplines as well as the fact that the disciplinary contexts represented in this body of literature seemed only mentioned in passing as extraneous contextual information prevented us making any claims about what might differentiate teacher leadership related to teaching English, as an example, as any different from teacher leadership related to teaching science.

This dearth of literature does not mean that disciplinary contexts are unimportant in shaping the work of teacher leaders. On the contrary, research in science education, for example, has revealed how disciplines bring with them particular ways of knowing both in terms of epistemic and epistemological resources (e.g., Berland & Hammer, 2012), and in the differences in semiotic registers that are activated within disciplinary epistemic work (e.g., Wilson, Boatright, & Landon-Hays, 2014). However, given our findings, little in the way of how the epistemological commitments of the disciplines, as well as how classroom activities in these disciplines targeting approximations of these commitments have to date been considered as they relate to teacher leadership. Therefore, we believe future research to understand teacher leadership will be greatly informed as more attention is given to the very specific disciplinary idiosyncrasies that exist. Specificity will help distinguish disciplinary learning as well as how disciplinary idiosyncrasies contribute to the selection of disciplinary teacher leaders, how they help shape and organize the work of teacher leaders, and how teacher leaders influence student learning within these disciplines.

This review not only worked to examine the context of teacher leadership, but it also sought to understand the extent to which the teacher leadership literature reviewed could be considered theoretical. Further consideration was given to which theories were found within the literature reviewed. With respect to the literature reviewed, it is difficult to assert that the literature on teacher leadership has remained atheoretical, as 33 (61%) pieces of literature did rely on at least one theory to inform the studies (see Table 3). However, given that the research included in this review is peer-reviewed, we were surprised to find that there were still so many researchers conducting what would be considered atheoretical research.

The Journal of Teacher Education, a top educational research journal (Impact Factor: 2.21; Ranking: 17 out of 219 in the Education & Educational Research category), requires a conceptual framework, which is defined as “connections to relevant constructs in literature” (Sage, 2015, para. 4). Another top educational research journal, the Journal of Research in Science Teaching (Impact Factor: 3.02; Ranking: 6 out of 219 in the Education & Educational Research category), indicates the following for submissions being considered for publication: “Articles are expected to reflect the best scholarly practice relevant to the study design. It is expected that you . . . establish and justify the guiding theoretical framework” (John Wiley & Sons, Inc., 2015, para. 3). These examples are shared to demonstrate the importance that top journals place on theoretical frameworks for grounding and building on educational research. There is value in using theory to inform research in a field so others may think beyond the results of one particular investigation and consider more generalizable perspectives that may provide insight across settings and investigations and inform practice (York-Barr & Duke, 2004).

We found at least 25 different theories identified in the research reviewed here. Among these, 10 studies (19%) reviewed here utilized distributed leadership to frame their research. This finding leads us to believe that there may be some agreement within the field as to a best theory with which to more generally frame research on teacher leadership. However, each author seemed to define distributed leadership slightly differently and emphasized different aspects of the theory, and there was quite a bit of variety in the foci of the studies. Topics explored using this framework included leadership structures and the sustainability of that leadership (Chamberland, 2009; Grant, 2009), school change and development (Hands, 2012; Harris & Townsend, 2007; Muijs & Harris, 2006), the conditions surrounding teacher leadership (Anderson, 2012; Grant, 2009; Hoang, 2008; Muijs & Harris, 2006; Supovitz, 2008; Vernon-Dotson & Floyd, 2012), and the impacts of teacher leadership (Gigante & Firestone, 2008; Muijs & Harris, 2006). So despite the fact that 19% of the literature reviewed here applied the same theoretical framework to research in teacher leadership, we would be hard-pressed to say that use of the framework allowed knowledge in the field to move forward in a unified direction.

We believe that it is appropriate to characterize the literature on teacher leadership as only partially theoretical as just over a majority of the literature was framed by theory. We recognize that the theory selected for any particular investigation into teacher leadership is largely dependent on the purposes of the research, and as such this helps explain the large variety of theory identified across the research reviewed. Nevertheless, we believe more consistency in the use of theory is needed if we expect to see some strands of research around teacher leadership building synergistically toward a theory of teacher leadership. Given this hope, we recommend that future research exploring teacher leadership consider the theories that have been applied previously as well as the emphasized aspects of those theories so as to work toward a theory of teacher leadership. Furthermore, we propose that future researchers using distributed leadership in particular consider and work to identify central features of this theory, as it appears to already have taken a somewhat prominent position as a theoretical lens for examining teacher leadership.

The Effects of Teacher Leadership and Those Things That Facilitate and Inhibit Such Effects

In the Results section, we revealed several of the effects of teacher leadership in terms of how it affects those taking up these roles, as well as the effects of teacher leaders on colleagues and schools. Beyond looking at these effects, we also examined those factors that facilitated or inhibited the impact of teacher leaders. Given the findings, we inferred that many of the positive or adverse effects of being a teacher leader seemed bound up in those things that either facilitate or inhibit the effectiveness of teacher leaders. Therefore, this section considers these (i.e., effects on those taking on teacher leadership roles, factors that facilitate or inhibit teacher leadership effectiveness) together.

One often-underreported outcome of teacher leadership is the effect it has on those taking up these roles. As an example, York-Barr and Duke (2004) examined the effects of teacher leaders and those factors that facilitated or inhibited teacher leaders’ effectiveness, but little attention was explicitly given to the ways in which teacher leadership transformed those taking on this role or the potential toll it might have taken. In fact, we did not originally intend to consider this outcome either, until it became apparent in the articles we reviewed that this might be an important component of supporting teacher leaders. For example, Durias (2010) identified how some teacher leaders felt that teacher leadership roles were a lot to take on, especially given what they felt were already heavy teaching workloads and questions about how their peers might react to them taking such roles. On the other hand, Chew and Andrews (2010) described how teacher leadership roles gave individuals a strong sense of purpose and satisfaction as they felt empowered in work they were doing to improve their schools.

Ultimately, our review uncovered the following four themes to describe the impact of teacher leadership roles on individuals taking on these roles: the stresses/difficulties, changing relationships with peers and administration, increased positive feelings and professional growth, and increased leadership capacity. As noted in the Results section, the first two of these (i.e., stresses/difficulties and changing relationships with peers and administration) were more associated with things that could negatively impact those taking on these roles. And, among those things that led to these themes were the already important and taxing roles teachers assumed in classrooms and the egalitarian norms that reverberate throughout the teaching profession. When we examined the literature to identify those factors that inhibited the effectiveness of teacher leadership, we noted themes that seemed to align with the adverse effects of teacher leadership on teacher leaders. Particularly, lack of time seems reasonably connected with the stresses and difficulties teacher leaders reported in these roles. And poor relationships, albeit not always the case, were at times tied to tensions that connected to challenging the egalitarian norms of the teaching profession (Friedman, 2011; Muijs & Harris, 2006). Furthermore, climate and structural factors, such as scheduling issues and norms that do not support the aims of teacher leadership, also seemed connected to the adverse effects some teacher leaders reported.

Conversely, the positive effects on teacher leaders as they took on these roles (i.e., increased positive feelings and professional growth and increased leadership capacity) also seemed well aligned with those things identified as essential elements in facilitating the effectiveness of teacher leadership. These positive outcomes can be seen as principals afforded teacher leaders autonomy to do their work or when principals played a large role in creating an environment that supported teacher leaders’ work. An example of this was seen in Gigante and Firestone (2008) as principals who supported the work of teacher leaders enabled those teacher leaders to more fully lead their schools, rather than simply serve as support personnel. These teacher leaders, in turn, felt more excited about and satisfied with their work. Certainly it can be seen how positive effects of being a teacher leader might emerge as the role is supported by principals and facilitating structures.

Beyond supportive environments arranged by principals facilitating effective teacher leadership, our review also revealed the importance of external supports. These external supports came in the form of training in content, pedagogy, and leadership and the collegial support networks and partnerships that emerged when multiple teacher leaders participated to take advantage of these supports in groups with other teacher leaders (e.g., Brosky, 2011; Yonezawa et al., 2011). These effects also seemed well aligned with positive benefits for teacher leaders as they took on their roles, namely increased positive feelings and professional growth.

What seemed most evident from considering the effects of teacher leadership and those things that facilitate and inhibit such effects, is how intricately connected the effects teacher leaders felt as part of taking on these roles were to the conditions within which their work was situated that either supported or inhibited this work. These findings point to the need for increased attention to the explicit articulation of teacher leaders’ roles, the time needed to accomplish these roles, their professional learning needs, and the provision of appropriate levels of autonomy. Additionally, supporting teacher leaders also requires some attention to power structures that are bound up in the relationships between teacher leaders and teachers connected to the egalitarian norms of the teaching profession. This finding suggests a need for future research to work at continuing to develop a better understanding about how climates can be constructed to reimagine the egalitarian norms associated with teaching or to reframe the work of teachers such that the role of a leader is seen not as a hierarchal position, but is instead seen as a mechanism for putting everyone in place to take advantage of the skills and commitments teachers possess. And finally, it seems imperative that more research be conducted to understand the effect teacher leadership has on those taking on these roles. Often the details of the effects teacher leadership had on those taking on these roles emerged in the research reviewed, but generally this was not the focus of the research. More focus in this area might, among other things, provide the beginnings of a teacher leadership professional learning trajectory for increased leadership capacity.

Finally as noted in the results, no research was found in the body of literature reviewed that examined the impact of teacher leaders on student learning. This omission stood out within the literature, particularly because a commitment to student learning is articulated in the ways that most define teacher leadership, including how we defined it for the purposes of this research. To be clear, we acknowledge that there is research linking overall school leadership and student learning (e.g., Leithwood & Jantzi, 2008; Leithwood, Patten, & Jantzi, 2010; Ma & Klinger, 2000; Robinson, Lloyd, & Rowe, 2008). However, there were no studies in the pieces of literature included in this review specifically linking teacher leadership to student learning, even though York-Barr and Duke (2004) identified this link as a need in 2004, and the educational climate has shifted toward an increased focus on accountability for student learning.

Although it has been recognized that there are inherent problems associated with documenting the value-added by teachers (or in this case, teacher leaders; e.g., Ballou & Springer, 2015), the lack of data on this matter has the potential to adversely affect educational policy. Therefore, we urge researchers to investigate possible correlations between teacher leadership specifically and student learning through either methodologies like those employed in establishing the link between overall school leadership and student learning (e.g., Leithwood et al., 2010; Leithwood & Jantzi, 2008; Ma & Klinger, 2000; Robinson et al., 2008) or by exploring methodologies more relevant and specifically tied to the explicit roles articulated for teacher leaders. Given the political emphasis on accountability, we believe that teacher leadership can be no more than a passing fad unless empirical research can support the value of teacher leadership in terms of student learning.

Conclusion and Significance

We recognize that there are high-quality pieces of research surrounding the topic of teacher leadership that did not meet our inclusion criteria, but it is surprising just how few pieces did meet all of our criteria. Fully 12 years ago, York-Barr and Duke (2004) were explicit in their call for literature based on empirical research with robust data collection measures. Based on our findings, the need for this type of literature on teacher leadership is still great. Particularly in light of the increased interest in teacher leadership as a key component of school reform, the inclusion of teacher leadership in teacher evaluations, and the challenge of teacher attrition, it is imperative that initiatives related to teacher leadership are grounded in high-quality research rather than “gut feelings” and descriptive literature. Otherwise, as Muijs and Harris (2006) have cautioned, the continued lack of empirical research may lead us to only view teacher leadership through rose-colored glasses, as advocacy in lieu of research, which will present “a very optimistic picture of the implementation of teacher leadership and its consequences” (p. 962).

Another concern that surfaced in our review was the lack of attention given to issues of equity and diversity. Brown, Benkovitz, Muttillo, and Urban (2011) argue that school leaders must attend to issues of equity and social justice because “a school culture that perpetuates the status quo and turns a blind eye to the social injustices that permeate our schools is not really ‘excellent’” (p. 86). Unfortunately, our review revealed that these critical issues are largely ignored in the teacher leadership literature and hold implications for future research.

Finally, it is also interesting to note the major topics associated with research on teacher leadership. Scholars in the last decade have continued the crusade to better understand what teacher leadership is and the conditions that may inhibit or support teacher leadership. However, it seems that few scholars have moved past these basic components to ask more difficult questions; questions that will require a wide spectrum of research methodologies and data sources, such as the following:

We, like others, believe that teacher leaders can play a central role in meeting the needs of students in schools. However, we predict that the role of teacher leader will continue to suffer from those factors that inhibit its effectiveness and the struggles teacher leaders encounter if researchers do not fill the gaps in the knowledge concerning teacher leadership with rigorous, empirically based evidence. As such, this review has identified those gaps and provided directions for future research.