A Conceptual Framework for Understanding Effective Professional Learning Community (PLC) Operation in Schools

This paper focuses on the development of professional learning communities (PLCs) in schools, which are communities of educators tasked with improving student learning outcomes. The purpose of this paper is twofold. First, the paper explores the central tenets of an effective PLC and contributes a definition of the concept to address much of contextual ambiguity found within the literature. Secondly, the paper employs this definition to inform the development of a conceptual framework for understanding effective PLC operation in schools, which can be used as a guide for PLC implementation at both the school and system levels.


Introduction
Social, economic, and political pressures are evident in educational reform movements as the effects of increased globalisation encroach upon the daily operations of teachers and their classrooms.Some have argued that, historically, attempts at education reform have mostly been ineffective, with a multiplexity of issues discussed as contributing factors: a non-collaborative school culture (Apple, 2012, Burns et al., 2018); the propensity of teachers to operate individually and independently (Mitchell & Sackney, 2011); ineffective teacher professional learning activities (Admiral et al., 2019, Edmunds, 2005); and the de-skilling of teachers' practice in combination with an intensified work load (Day & Sachs, 2004) to name a few.
A crucial element of education reform has been to navigate the complexity of ensuring that teachers have the skills and knowledge necessary to educate effectively in a rapidly changing, fluid, and diverse socio-political and socioeconomic environment.Owen (2014) remarked that 'highlevel educational outcomes for students are being increasingly linked with quality teachers and there is a need for ongoing professional learning to ensure that teaching practices are updated within an era of considerable educational reform ' (p. 55).This view is congruent with that of Day and Sachs (2004) who explained that 'the impact of changing economic, social, and knowledge contexts upon the education service as a whole has caused a move from the traditional post-war model of the autonomous professional in which decisions about the curriculum, teaching, learning and assessment are the business of teachers' (p.3).The imperatives for education systems to deliver education programmes that are efficient, effective, and economical are common drivers of education reform initiatives, with enhancing teacher professionalism a major target of intervention (Day & Sachs, 2004).However, at the centre of the professionalism argument, teachers have traditionally 'been positioned in the debate as objects to be manipulated and controlled rather than as professional creators of a learning culture' (Mitchell & Sackney, 2011, p. 1).
As a result of the increased professionalism required of teachers, the resultant demand inherent in educational reform is for higher quality teachers who are 'well qualified, highly motivated, knowledgeable and skilful, not only at the point of entry into teaching but also throughout their careers' (Day & Sachs, 2004, pp. 3-4).Consequently, professional learning is considered an ongoing expectation for teachers as the profession pushes towards an increased level of professionalism amidst a new global landscape (Day & Sachs, 2004, Mitchell & Sackney, 2011, Vangrieken et al., 2017).This push aims to define teachers less as functionaries and more as professionals, placing the practice of teaching alongside that of more esteemed professions such as medicine, law, accounting, and architecture (Apple, 2012).Although the reasoning for the move towards increased professionalism is to enhance the quality of teachers in the profession, most education reform initiatives have traditionally been administered through a top-down approach with little attention paid to teacher collaboration and learning (Apple, 2012;Fullan et al., 2015).The effectiveness of top-down approaches to education reform have been deemed ineffective over the last decades (Apple, 2012;Fullan et al., 2015;Hardy & Melville, 2019;Mitchell & Sackney, 2011;Nielsen & Lockhart, 2020), which has resulted in the search for new methods of professional learning for teachers within schools.Fullan et al. (2015) remarked that this has meant a move from focussing on external accountability measures to a (re)focus on building an internal accountability system within the teaching profession; an approach that focuses on collective responsibility at the local school level and the building of the professional capital of all teachers and leaders throughout broader education systems.
Further, as an exacerbating factor, it is acknowledged that the traditional workshop model of teacher professional learning that has long existed in education is ineffective (Admiral et al., 2019, Vescio et al., 2008, Vangrieken et al., 2017).Some have argued that it maintains and reinforces teacher isolation (Mitchell & Sackney, 2011, Vangrieken et al., 2017), which limits the opportunities for teachers to learn from and through each other's practice (Mitchell & Sackney, 2011).Resultantly, there has been a growing appreciation of teachers collaboratively reflecting upon practice together to embrace new pedagogical approaches for the betterment of students' learning (Vangrieken et al., 2017).Vescio et al. (2008) noted that the movement away from workshop models of teacher profession learning has led to a recognition that 'knowledge is situated in the day-to-day lived experiences of teachers and best understood through critical reflection with others who share the same experience' (p.81).Thus, by actively engaging teachers in collaboration, and away from the isolated methods of workshops, teachers 'increase their professional knowledge and enhance student learning' (p.81) at a collective level rather than an individual level.
We see, then, the existence of an enhanced focus on embracing and supporting teachers' professional learning in collaboration with one another to ensure that schools are successful in enhancing students' learning outcomes in a changing globalised landscape (Vangrieken et al., 2017).Hord and Roy (2014) expressed the need for a narrative on teachers' professional learning 'that honours teacher knowledge and craft as key ingredients in equalising outcomes' (p. 3) and that the '[implementation of] professional learning communities supports such a narrative' (p.3).
Professional learning communities (PLCs) provide an alternative approach to top-down mandates, with effective PLCs considered to be those that adopt an inside-out approach, emphasising and facilitating collaborative teacher learning in the pursuit of enhanced student learning outcomes (Mitchell & Sackney, 2011, Vangrieken et al., 2017).The remainder of this paper is focused on reviewing the literature pertaining to teachers' collaborative professional learning in and through PLCs, which, as stated, is at the core of effective PLC operation.From this review, a conceptual framework for effective PLC operation in schools is proposed, which can be used to assist school leaders, system leaders, and teachers to understand the link between themselves and student learning outcomes when reviewing the effectiveness of their PLCs.

The Literature Search Process
The author employed a structured literature search strategy to inform the review and the development of the conceptual framework that is presented at the end of the paper.Initially, the search descriptor of 'professional learning community' yielded in excess of 100,000 publications.Clearly, PLCs have much focus in the existing literature and such an expansive results list is not conducive to a focused literature review.Therefore, given the focus of the paper was to explore effective PLCs, and the nature of teachers' collaborative learning and subsequent influence on students' learning outcomes, a more targeted Boolean search was considered necessary.
The author searched for publications related to PLCs using the terms 'professional learning communit* OR plc OR learning comm*', and combined this with search terms related to effectiveness such as 'effective* OR success* OR fail*', terms related to teacher learning and collaboration such as 'teacher learn* OR teacher professional learn* OR teacher collaboration', and terms related to outcomes such as 'outcome OR effect OR results'.This yielded a much more manageable pool of 147 publications for the author to consider.When the 'peer-reviewed', 'academic journal', and 'English' filters were applied to this search, the results were filtered to 86 publications.Given the scope and size of this paper, not all 86 publications were used to inform the review.Some publications were excluded because they were irrelevant to PLCs specifically, they were repetitive publications, or they did not provide sufficient focus on teachers' collaborative learning and PLC effectiveness to warrant inclusion.Furthermore, some publications were read by the author but were not included in the review as the purpose of the paper was not to provide a systematic overview of all literature pertaining to effective PLCs, rather it was to build a practical understanding of the interplay of factors that culminate in PLC effectiveness.As such, the included publications best represented many of the themes discussed across all 86 publications.
Additional publications were mined from the reference lists of included publications, linking the author to some earlier work on the initial conception of PLCs from seminal authors in the field.Most publications used to inform this review were nonempirical, descriptive studies.Indeed, there were scant empirical studies that detailed how teachers' collaborative learning in PLCs led to enhanced student learning outcomes in the form of quantitative data, with most studies only indicating improvement in student learning outcomes through the subjective opinions of teachers and school leaders.Interestingly, the voices of students are largely absent in the PLC literature.The lack of empirical focus and student voice indicates future avenues of inquiry into PLC effectiveness.Furthermore, given that this review was not conducted systematically, the author acknowledges that this is both a limitation of the paper and an opportunity to direct the focus of future research on the relationship between teachers' collaborative learning and PLC effectiveness.

A Case of Contextual Ambiguity
The last decades have seen a plethora of research on PLCs, and this has led to a case of contextual ambiguity as broad understandings of the concept have proliferated.Indeed, the seminal work of DuFour et al. (2005) explained that as PLCs have become more popular, they have been used to 'describe every imaginable combination of individuals with an interest in education' (p.31), and the concept is 'used so ubiquitously that it is in danger of losing all meaning' (p.31).Kilpatrick et al. (2003) added that the concept of a PLC is 'used variously within the literature, often without explicit definition' (p.2).Resultantly, there are multiple interpretations of the concept and a central definition does not exist (Bolam et al., 2005, Cranston, 2011, Gray & Summers, 2015, Nielsen & Lockhart, 2020).Large-scale systematic reviews on PLCs such as Vangrieken et al. (2017) and Vescio et al. (2008) have elaborated on the contextual nature of defining PLCs, explaining that PLCs are often referred to differently in the literature: learning communities, teacher community, scientific community, professional community, collaborative professional community, educator inquiry group, communities of practice, and critical friends group as examples.
With the concept of PLCs so broadly attributed to, there is an opaqueness surrounding how a PLC is defined.From a research perspective, Vangrieken et al. (2017) lamented that the proliferation of terminology used to describe PLCs makes it unclear whether the results of different studies can be justly compared or whether different concepts, themes, and practices are being investigated.Vangrieken et al. (2017) concluded that an important issue for future research into PLCs is the inclusion of a clarified description of the concept under investigation.

A Synthesised Definition of a PLC
Much has been written on the characteristics that make up an effective PLC.Bolam et al. (2005) captured the essence of this body of knowledge in their report on creating and sustaining effective PLCs.Bolam et al. (2005) reported that effective PLCs generally displayed eight characteristics: (1) shared values and vision about pupil learning and leadership; (2) collective responsibility for pupil learning; (3) collaboration focused on learning; (4) individual and collective professional learning; (5) reflective professional enquiry; (6) openness, networks, and partnerships; (7) inclusive membership; and (8) mutual trust, respect, and support.Additionally, Bolam et al. (2005) explained that effective PLCs are developed and maintained by four broad structural processes: (1) optimising resources and structures; (2) promoting individual and collective professional learning; (3) evaluating and sustaining the PLC; and (4) leading and managing.
Others, too, share the view that these characteristics are important for effective PLCs.Hord (2009) explained that an effective PLC is mostly characterised by a continuous professional learning environment that is focused on improving teacher quality and improving student outcomes.Hord and Roy (2014) explained that the soul of a PLC is teachers engaging in 'intentional learning directed towards student benefits' (p.23).Important preconditions to facilitating this are conducive structural conditions, leadership policies and practices, and shared beliefs and values that enable the PLC to work towards a common vision (Hord & Roy, 2014).With these preconditions in place, trusting relationships and the support of peers enable teachers in the PLC to focus their efforts on intentional collaborative learning, committed to continuous improvement of student learning outcomes.DuFour et al. (2005, p. xii) emphasised a collaborative, continuous improvement, and results focused approach encapsulated by their definition of a PLC: It starts with a group of teachers who meet regularly as a team to identify essential and valued student learning, develop common formative assessments, analyse current levels of achievement, set achievement goals, share strategies, and then create lessons to improve upon those levels.Picture these teams of teachers implementing these new lessons, continuously assessing their results, and then adjusting their lessons in light of those results.
Adopting a broader perspective, Kilpatrick et al. (2003, p. 2) provided a distinction between two separate categories that subsume the collaborative, continuous improvement, and results-focused nature of PLCs: The first focuses on the human element of communities, and the profits that accrue from building on the synergies of individuals in common locations or with common interests as they work towards sharing understandings, skills and knowledge for shared purposes.The second is focused on curricular structures (i.e. an inanimate structure) as the means to developing 'deeper' learning of (implied) predetermined curricular content.Mitchell and Sackney (2011, p. 10) further supported the notion of broad categories of distinction by discussing that within a PLC, each person is a worthwhile participant in the tasks, activities, and responsibilities of the community, and people work together in a spirit of experimentation and risk-taking to improve the education experience of all individuals in the school.This is the cognitive component.Furthermore, each person deserves the support and care of other school members, and people work together in a spirit of trust and mutual respect.This is the affective component.
The literature discussed highlights that a PLC can be broken down into two overarching themes of modalitythe modality of humanistic communities, which is concerned with the affirmative dimension of PLC's: the production and maintenance of an inclusive, supportive, and encouraging community environment, and the presence of collective responsibility and mutual goal alignment.Secondly, the modality of curricular structures, which is concerned with cognitive dimension of PLC's: continuous improvement in the form of improved teacher quality and student outcomes.In other words, professional learning that occurs through the continual analysis of student assessment data to inform a critical and reflective interrogation of practice.In synthesis, a definition of a PLC for this paper is constructed by referring to both modalities: A professional learning community is as a group of educators motivated by continuous improvement, collective responsibility, and mutual goal alignment, who engage collaboratively in professional learning to increase educator effectiveness and to improve student outcomes.This is achieved by the educators sharing and critically interrogating their practice in an ongoing, reflective, inclusive, learning-oriented, and growth-promoting way, underpinned by a high level of collegial trust and a supportive school environment.
The purpose of providing this definition is not to theorise a comprehensive and exhaustive definition of a PLC.Rather, it helps frame the elements which are necessary to build and sustain PLC effectiveness.

Elements of an Effective PLC
The last decades of research on PLCs has seen an almost ubiquitous agreement that effective PLCs as those where teachers engage in collaborative reflective practice to enhance their learning and to improve student outcomes (Bolam et al., 2005, Day & Sachs, 2004, DuFour & Eaker, 1998, Garrett, 2010, Hord, 2009, Hord & Roy, 2014;Mitchell & Sackney, 2011, Vangrieken et al., 2017).However, for all that has been written about the elements of an effective PLC, as well as existing conceptual models that have been developed to visually show what these elements are, there has been a dearth of scholarly attention afforded to how the elements of an effective PLC relate to, and are dependent, upon one another.For example, although Hord and Roy's (2014) model highlighted that conducive structural conditions, supportive leadership policies and practices, and shared beliefs and values must be in place for teachers to teachers to intentionally learn together within a PLC, their model didn't connect how having shared values and vision is often predicated on enabling school structures, such as allocated time and space for teachers to discuss their individual value systems which are not fixed and may change over time.This paper now turns towards a discussion on the elements of an effective PLC, notably their connectedness and how enabling school structures assist in the development and maintenance of shared values and vision, the promotion of trust, and, in turn, an environment that sees teachers collaboratively reflecting together to change their practice to enhance students' learning outcomes.Gray et al. (2015) explained that enabling school structures can be defined by teachers' belief that the leadership and rules of the school help support them in their work.This is represented by leadership that helps rather than hinders, and rules and regulations within the school that guide collaborative problem solving rather than the punishment of failure (Hoy, 2003).Furthermore, teachers and leaders work together through a process of shared decision making amidst the hierarchical structures that are evident in most schools.With this, enabling school structures see the principal and teachers working cooperatively across mutually recognised and defined authority boundaries, whilst retaining their respective roles within the school.Principals are responsible for establishing enabling school structures through policies, rules, and shared decisionmaking to ensure that the life of a PLC is one that is sustainable over time (Bolam et al., 2005, Gray & Summers, 2015).When these structures are in place, 'schools develop an atmosphere of trust and teacher commitment to the school and its mission' (Hoy, 2003, p. 91), and teachers are more likely to maintain an action orientated focus on continuous school improvement in a PLC (Zheng et al., 2016).

Shared Vision and Values
A common vision becomes an image in which all teachers can refer to and work towards.Hord and Sommers (2008) explained that because values and beliefs drive human action, it is important that a PLC is defined by a shared common vision that underpins the practices that emanate from it.Mitchell and Sackney (2011) noted that a common vision draws together the aspirations of all affected parties, so as to 'provide appropriate direction and alignment for the educational activities in the school' (p.11).Effective PLC operation is predicated upon teachers and school leaders having a shared vision to improve student outcomes (DuFour & Eaker, 1998,Hord & Sommers, 2008, Van Meeuwen et al., 2020, Vescio et al., 2008).With this shared vision in place, teachers in a PLC direct their attention towards improving instructional practices to enhance student outcome data (Beddoes et al., 2020;Vescio et al., 2008).

Collegial Trust
Pivotal to effective PLC operation is collegial trust amongst teachers (Gray & Summers, 2015, Mitchell & Sackney, 2011, Yin et al., 2019, Zheng et al., 2016).Gray et al. (2015) defined collegial trust as the belief 'that teachers can depend on one another in a difficult situation; teachers can rely on the integrity of their colleagues' (p.876).Hord and Roy (2014) added that trust in schools is a reciprocal process between teachers.Tschannen-Moran and Hoy (2000) extended this understanding further be defining trust as 'one party's willingness to be vulnerable to another party based on the confidence that the latter party is (a) benevolent, (b) reliable, (c) competent, (d) honest, and (e) open' (p.556).
Tschannen-Moran and Hoy (2000) delineated between three kinds of trust in schools: (1) faculty trust in the principal; (2) trust in colleagues; and (3) trust in clients such as parents and students.Bryk and Schneider (2002) added to this with their conception of three forms of trust within a school: (1) organic; (2) contractual; and (3) relational trust.Organic trust relates to the belief in the moral authority of an organisationconsensus about beliefs and a shared common vision.Contractual trust is concerned with an instrumental relationship to an organisationmutually defined performance expectations are explicit, and metrics are in place to judge such performance.Relational trust is concerned with the interrelationships that are developed within a school contextrole relationships in which 'each party holds an understanding of their role obligation and have expectations about the role obligation of the other' (p.20).Bryk and Schneider (2002) posited that schools are more reliant onrelational trust over organic and contractual trust.But because of the desire for shared values and vision as a core component of a PLC, there is an element of organic trust that is generated in and through the operation of PLCs (Hord & Roy, 2014;Kalkan, 2016;Mitchell & Sackney, 2011).However, as PLCs are largely collaborative endeavours, they are predominantly dependent upon relational trust amongst teachers and school leaders.This is of particular importance to discuss when considering teacher learning within a PLC for several reasons: trust reduces teacher vulnerability; it encourages innovation in the classroom to develop and enhance instruction; it facilitates the opportunity of public problem solving; and it creates the moral environment necessary to implement successful school initiatives (Bryk & Schneider, 2002, p. 117).Hattie (2009) added that 'trust also maximises the occurrence of error and thus allows feedback to be powerful in use and effectiveness ' (p. 240).
Within PLCs, the professional learning of teachers is reliant upon teachers collaboratively reflecting with one another, and collegial trust seen to be the foundation for this to occur (Mitchell & Sackney, 2011).Teachers who view their colleagues in a PLC as honest, open, competent, reliable, and professional tend to have more trust in them, which leads to a greater possibility of reflective practice occurring between teachers within a PLC (Gray et al., 2015, Zheng et al., 2016).

Collaborative Reflective Practice
An established body of research confirms that collaborative reflective practice amongst teachers leads to a higher incidence of change in teacher practice for the betterment of student outcomes (Little, 2020;McGarr et al., 2019;Mitchell & Sackney, 2011;Servage, 2008;Sharma et al., 2011;Turhan & Kirkgoz, 2018;Weller, 2019).However, as Alzayed and Alabdulkareem (2020) suggested, 'this influence greatly depends on providing opportunities that encourage teachers to reflect on their teaching practices and students' learning' (p.3).
Hord and Roy (2014) discussed the work of Schön (1983) and explained that the development of PLCs owe much to his seminal work on the power of reflective practice.Schön (1983, p. 68) defines the concept of reflective practice as when, the practitioner allows himself to experience surprise, puzzlement, or confusion in a situation which he finds uncertain or unique.He reflects on the phenomenon before him, and on the prior understandings which have been implicit in his behaviour.He carries out an experiment which serves to generate both a new understanding of the phenomenon and a change in the situation.
The two types of reflective practicereflection-in-action and reflection-on-actionare both evident in PLCs, but it is reflection-on-action that is more prominent (Alzayed & Alabdulkareem, 2020, Hord & Roy, 2014).Alzayed and Alabdulkareem (2020) explained that reflection-in-action refers to when practitioners make decisions during professional situations based on information derived from their implicit knowledge, whereas reflection-on-action refers to reflection on professional situations after they occur and deciding what can be done differently in future practice.Hord and Roy (2014) believed that 'it is reflection-on-action, which entails opportunities for sharing ideas, looking at practice with a critical eye, and jointly identifying problems of practice and hypothesising about solutions, that is central to professional learning communities in education' (p.4).Hord and Sommers (2008) saw reflective practice as consisting of elements of collective inquiry, stating that 'the learning in successful learning communities is based on collegial inquiry and on reflection by the participants and their dialogue about their reflection' (p.12).The basis of such inquiry for reflection can be said to be 'a willingness by each teacher to openly and respectfully examine current practices or "craft" by identifying those that have the greatest impact on student learning towards sound teaching and learning principles' (Beddoes et al., 2020, p. 13).Alzayed and Alabdulkareem (2020) added that although '[r]eflection might be an individual effort … it is more effective if it is shared with others in dialogue and inquiry groups' (p. 3) Thus, the collaborative environment of a PLC can be a catalyst for both individual and group learning through reflection-on-practice.Beltramo (2020) discussed notions of critical reflection in his study of the relationship between cogenerative dialogue and teacher reflection.Beltramo (2020) referred to three levels of reflection: the first level where teachers consider the technical aspects of their instruction; the second level where the focus shifts by weighing those instructional decisions against evidence of student learning; and the third level, that of critical reflection, where 'teachers consider each element of their practice in light of education policies, social dynamics, and/or issues of equity that mediate teaching' (p.88).Beltramo (2020) noted that because educational reforms and policies often solely frame educational issues as those within classrooms, taking a critically reflective approach analyses and interrogates these issues so as '(a) to identify and address discrepancies in power relations, as well as the competing values, assumptions, and ideologies, underlying them, and (b) to develop equity-oriented pedagogies that can afford all students robust opportunities for learning ' (p. 88).Reflection in this sense allows a teacher to critically challenge the presuppositions that direct their existing instructional practices which can lead to an emancipatory learning experience (Jones, 2018).In other words, critical reflection enables teachers 'to learn about the nuances of their craft, develop the principles of their identities, and seek liberation (for themselves and their students) through the construction of more equitable learning opportunities' (p.88).
Mitchell and Sackney (2011) called for collaborative reflection within PLCs to critically address the problem of teachers having a distorted connection between espoused theory and theory-in-use in relation to their practice.Mitchell and Sackney (2011, p. 21) explained that, espoused theory is the set of assumptions, beliefs, and values that people publicly declare.It is what they say they believe, what they advocate in open discussions, and they promote in professional discourse.It usually consists of the 'best practice' or the standard rhetoric currently in vogue.Theory-in-use, on the other hand, is the set of assumptions, beliefs, and values that people do not necessarily declare but they follow in practice.It is what be seen underneath their decisions, actions, interactions, and reactions, and some of it might not always be stellar.The problem is not that these two sets of theories coexist but that they are often not aligned.
To undertake such an evaluation holds both the iron fist and the velvet glove of critical reflection for teachers.On the one hand, it is said to lead to a deep intimacy with one's professional theory-in-use and the gaps that are needed to address in order to improve practice.On the other hand, it means confronting unpleasant truths about the discord between espoused theory and theory-in-use, which can lead to the realisation that instructional changes are needed.Such depth of reflection becomes a question of identityboth personal and professionalwhich, ipso facto, presents an emotional challenge as well as a practical one.PLCs, then, become a platform whereby teachers not only have their practice critically appraised by themselves, but also by other teachers through critical dialogue in the PLC; that is, they lay bare their assumptions, beliefs, strengths, weaknesses, and motives to their colleagues and have them challenged, which is purported to lead to deep professional change.This is a daunting professional demand placed upon teachers.Thus, it cannot be seen as a surprise if some teachers are threatened by the collaborative environment of a PLC and continue to work on the technical aspects of practice that require no depth of critical reflection (Servage, 2008).
In their study about the challenges and possibilities of critical reflection in education, Šarić and Šteh (2017) concluded that 'there are no quick fixes with regard to encouraging teachers' professional development or to developing critical reflection' (p.81).Šarić and Šteh (2017) revealed that because professional development initiatives such as PLCs often require 'deep cultural change' (p.81), the emergence of 'critical reflection is only possible in the environments in which doubt about certain views and actions is allowed and where individuals are willing to doubt and broaden the limits of their comfort zones' (p.81).It is, then, important to build collegial trust in and through a PLC so that teachers feel safe and willing to engage in critical reflection with one another.As Hord and Roy (2014) summarised, talking openly and honestly about problems of practice 'becomes less threatening in a collaborative culture in which norms of openness and trust are enacted' (p.15).

Discussion
When PLCs are Effective: Improved Student Outcomes and Change in Teachers' Practice Guskey (2002) proposed that professional learning for teachers should lead to a change in teacher practices that ultimately have a positive effect on student outcomes.Guskey (2002) added that as a result of improved student learning outcomes, teachers experience changes in their existing attitudes and beliefs towards their students.Thus, there is a feedback loop evident where teachers are able to alter their attitudes and beliefs about a student or group of students based upon the changes in outcomes that they see.
Similarly, Samaranayake et al. (2018) believed that an essential component in improving student outcomes is making necessary changes to teaching processes by learning new knowledge and skills.Samaranayake et al. (2018) explained that teacher collaboration is of fundamental importance to teacher learning, which coincides with changes in teacher knowledge, attitudes, and beliefs, and can result in changes to instructional practices to enhance student outcomes.The link between teacher collaborative learning, teacher change, and student outcomes is further emphasised by Hattie (2009): 'to engender reform that will make the difference requires incentives primarily in terms of teachers learning about their teaching, about what is working and for whom, and from sharing evidence of the effectiveness of their methods ' (pp. 240-241).Table 1 draws upon the effective PLC literature and details the outcomes that can ensue from effective PLC operation.
When PLCs are Ineffective: PLC Lite and the Absence of Change in Teachers' Practice DuFour and Reeves (2016) explained that many schools that have adopted the PLC process are operating in a 'PLC lite' mode.A PLC Lite is described by DuFour and Reeves (2016) as PLCs that operate on a surface level, that is, they are operational; however, they do not proceed to improve student learning outcomes.As DuFour and Reeves (2016, p. 69) explained: Educators rename their traditional faculty or department meetings as PLC meetings, engage in book studies that result in no action, or devote collaborative time to topics that have no effect on student achievementall in the name of the PLC process.These activities fail to embrace the central tenets of the PLC process and won't lead to higher levels of learning for students or adults.
Within their discussion, DuFour and Reeves (2016) point to three main facets of PLC operations that can lead to the shallow nature of a PLC Lite: (1) PLCs that reproduce formative assessments to mimic state tests and do not challenge students to show what they know in other ways; (2) PLCs that have no processes for collective analysis of student data; and (3) PLCs that reproduce and recycle previous unsuccessful teaching practices as student learning interventions.When these factors enter a PLC, DuFour and Reeves (2016) contend that teachers spend their time discussing educational standards, student behaviours, and parent complaintsconversations that are not seen to represent the work that occurs in effective PLCs.
Understanding the reasons why some PLCs are operating in PLC Lite mode is an important consideration if schools are to avoid them.Riggins and Knowles (2020) explained that ineffective school leadership, teachers working in isolation, and PLCs not working on the right work are the main contributing factors to the formation of a PLC Lite.In their study of a secondary school that had implemented a PLC but with little to no indication of improving student outcomes, Sims and Penny (2014) noted two key issues that negatively influenced the PLC: (1) teachers believed there was insufficient time for the PLC to engage with deep and rich work and (2) members of leadership appearing disinterested with the PLC process.Some teachers in the study expressed that the PLC had a negative effect on their practice as they felt that the PLC limited their individuality and creativity of practice.Sims and Penny (2014) concluded that an  Chou, 2011;Lee, 2020;Little, 2020;Moulakdi & Bouchamma, 2020;Tam, 2015;Thompson et al., 2004;Vanblaere & Devos, 2016;Voelkel & Chrispeels, 2017 Change in teacher knowledge • Increased subject content knowledge • Increased pedagogical content knowledge Christ et al., 2017;Crippen et al., 2010;Dogan et al., 2016 Change in teacher practice • An enhanced focus on a student-centred teaching and learning • An enhanced focus on inquiry-based teaching Chou, 2011;Dogan et al., 2016;Dogan & Adams, 2018;Jones et al., 2013;Little, 2020 over focus on data and assessments within the PLC was believed to interfere with the teachers broader need for collaboration, and as such, collaboration was confined to the narrow scope of content related discourse.Sims and Penny (2014, p. 43) explained this further by revealing that the teachers in their study, Lamented a lack of comprehensive discussion of teaching from the point of view of both content and method.Because the analysis focused on students who were not performing up to par, when the conversation did turn to pedagogy, it only dealt with narrow remediation of inadequately supported content knowledge.The limitation of this in-the-weeds approach was most clearly demonstrated when assessments revealed that student performance was low overall, but with no clear commonality with regard to content learning deficiencies.
Although the work within PLCs is guided by data-driven decision-making processes, an over reliance on data can be counterproductive to teachers' learning, and, subsequently, the improvement of student learning outcomes.In their study, Sims and Penny (2014) showed that the teachers within a PLC did not see an improvement in their students' achievement data, notably because the teachers were not prompted by collaborative critical reflection to think in different or more holistic ways, and as such, the PLC did not impact teachers' learning.Sims and Penny (2014) recommended that in addition to a focus on student learning data, PLCs should include teachers engaging in open and reflective conversation so that they are afforded 'opportunities to question, investigate, and find solutions concerning aspects of their practice' (p.43).Such an approach values teacher learning and collaboration as part of an effective PLCan approach that takes a more holistic approach over one that features an over reliance on data.
Hardy and Melville (2019) shared a similar viewpoint as Sims and Penny (2014) in their study around policy-maker influence on PLCs in terms of an increased focus on the achievement of student learning outcomes.Because of the over reliance on data and improving student outcomes, they found that PLCs were often associated with compliance, rather than substantive engagement.Hardy and Melville (2019) concluded that PLCs in their study did not reflect the sorts of active, teacher-led inquiry into elements of their practice for enhanced student learning that characterises the literature; notably because there was an over focus on four key elements within the PLC: (1) an increased accountability for teachers' practices; standardisation of work practices; (2) managerial control; (3) attention to external evaluation processes; and (4) constant pressure around performance.Hardy and Melville (2019) noted that such an approach represented organisational professionalism as a result of adherence to policy mandates.Consequently, Hardy and Melville (2019) argued that PLCs should focus more on developing occupational professionalism, that is, a focus on teachers being more autonomous, collegial, and using professional ethics as the main form of accountability in a PLC.

Conclusion and Conceptual Framework
The purpose of this paper was to contribute to the body of literature that has explored effective PLC operation in schools.In addition, and in consideration of the literature that has been discussed, this paper proposes a conceptual framework for understanding how effective PLCs operate (Figure 1).The conceptual framework demonstrates how PLCs can result in teacher learning through collaborative reflective practice, leading to teacher change and enhanced student outcomes.
At its base, the conceptual framework establishes that an effective PLC is first and foremost underpinned by a foundation of enabling school structures that are inclusive of leadership support.When enabling school structures are in place, it can lead to the promotion of relational trust in the form of trust amongst colleagues, and also organic trust in the form of consensus about the common vision and purpose of the PLC.This promotes an environment of collaborative reflective practice and enhances teacher learning.Teacher learning leads to a change in knowledge, skills, attitudes, and/ or beliefs, which are interrelated and connected.This can then lead to a change in teacher practice.Teacher practice and student outcomes are inexplicably linked and interrelated.Student outcome data are collected and flow back into collaborative reflective practice within the PLC as a way of sustaining a focus on continuous school improvement.However, it is important that data promotes collaborative reflective practice amongst teachers rather than becoming the sole reified focus within the PLC.
The conceptual framework can be used by PLC researchers, teachers, and school leaders to understand the link between enabling school structures and improved student outcomes within a PLC.It provides a common anchor point for discussing effective and ineffective PLCs and can be used at both the school and system level.Using the conceptual framework enables targeted insights into how best to support teachers to engage in collaborative reflective practice, engendering the goal of enhancing their professional learning in and through PLCs as a conduit for improving students' learning outcomes.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figure 1 .
Figure 1.A conceptual framework for understanding effective PLC operation in schools.

Table 1 .
Outcomes of Effective PLCs.