The use of a teaching practice known as ‘differentiation’ has become more common over time as educators have sought to respond to increases in the diversity of students enrolling in their local school. The term is now used widely by Australian teachers and school leaders, as well as policy makers.

For example, according to the Australian Professional Standards for Teachers, Australian teachers are expected to “Differentiate teaching to meet the specific learning needs of students across the full range of abilities”. They are also expected to implement “Quality Differentiated Teaching Practice to meet the diversity of learners within their classroom”, as part of the Nationally Consistent Collection of Data on School Students with Disability.

Being able to claim and demonstrate high-quality differentiation in the classroom now informs teacher promotion and school improvement review processes. It is also one way schools can meet their obligations under the Disability Standards for Education, as differentiation is a means through which teachers make reasonable adjustments to curriculum, pedagogy, assessment and the learning environment.

Given the emphasis in Australian legislation, policy and practice, it is important that when we refer to differentiation, we are all talking about the same thing. However, if you were to ask 10 teachers what differentiation means and how they implement it in their classrooms, you could receive 10 different responses.

As education researchers with expertise in inclusive education, we were interested in the spread of differentiation and what it means to teachers and researchers. We are also curious as to the basis for some especially loud criticisms of it.

Criticisms based on inconsistencies and misconceptions

There are a range of criticisms of differentiation including that it:

• Requires teachers to provide every student with individualised lessons
• Increases teachers’ workloads
• Makes teachers’ work complicated
• Waters down the curriculum
• Lowers expectations of students and their exposure to the academic curriculum
• Is too difficult to implement in mainstream classrooms
• Is inconsistent with evidence-based approaches such as Response to Intervention
• Lacks evidence of effectiveness.

We began this review because we knew that several of these criticisms are just plain wrong. For example, the goal of differentiation is to stretch students beyond what they can already do but not so much that they experience frustration or failure. It is about “teaching up”, not “watering down” the curriculum, where teachers raise expectations for all students and provide appropriate scaffolds to help students to experience success.

It is also not about “‘individualised instruction’”; rather, it offers “multiple avenues to learning” through proactive design. In fact, its emphasis on proactive planning aims to reduce teacher workload, not add to it. By building in accessibility and flexibility, it has the potential to save teachers time in the long run by teaching more efficiently and effectively from the outset, preventing the need to spend additional time replanning and reteaching the curriculum.

Some of these criticisms stem from a lack of definitional clarity. This problem was highlighted in Australian research as long ago as 2014, and has been recently confirmed by two reviews from the United States, published in 2019 and 2020.

A consistent and clear understanding of what is meant by differentiation is therefore vital in order to examine the validity of these criticisms and consider whether they correctly construe the motivation for its use.

To examine these issues in more depth, we undertook a comprehensive scoping review to synthesise what can be known from existing studies. We found that the research literature on differentiation contains a range of definitional inconsistencies and misconceptions about how differentiation is conceptualised and implemented.

This is a huge problem. How can we talk about, implement or indeed criticise differentiation in our schools if we are talking about and doing different things?

So let’s start with a definition

It is essential for teachers and researchers to work from a common understanding of differentiation and so as part of our research we first provided a clear definition. To construct our definition we drew on the work of Carol Ann Tomlinson, an American educator, author and speaker who is well known for her work with differentiated instruction over the last two decades.

This is what we, and others in inclusive education, mean when we use the term. It is:

the use of proactive planning and inclusive practices to create accessible learning experiences to meet the needs of all learners in heterogeneous classrooms, using flexible within-class grouping, as opposed to fixed ability grouping, year-level streaming or withdrawal to separate programs.

For further clarification, we use the term flexible grouping to refer to varied use of whole class and individual learning, alongside heterogeneous and homogeneous small group learning according to interest, learning profile, and readiness.

Our research

We conducted our scoping review of all peer-reviewed research literature published between 1999, when Carol Tomlinson published her influential book, The differentiated classroom: Responding to the needs of all learners, and 2019, the year we concluded our search. Searches of seven research databases netted 1,235 records, to which we added another six identified through hand-searching.

Our definition was broad and theoretically derived and hinged on practices enacted to meet the needs of all learners in heterogeneous classrooms. We therefore excluded studies that incorporated practices inconsistent with this definition such as ability grouping, year-level streaming or studies in which there was withdrawal of students to separate programs. We also excluded studies informed by misguided practices such as differentiating for learning styles or intelligence strengths, or by ability grouping and segregation as there is either no evidence to support their use or because there is clear evidence against their use.

Multiple screening stages (for those interested in the details of our research process, particularly when it comes to what we excluded and why, please go to our full paper) resulted in a final sample of 34 journal articles. Our review of these 34 articles was guided by two research questions, both of which were exploratory, rather than explanatory:

1. Are there any discernible patterns in peer-reviewed empirical research conducted on differentiation in school settings between 1999 and 2019 with regard to aim, location, school phase, participant types and methods used?
2. What are the principal research foci of these studies, how do they conceptualise and research differentiation, and how might research on differentiation be improved?

Findings

Our findings on the research evidence on differentiation were variously pleasing, surprising and of great concern to us. We found that while some teachers can find differentiation a challenge to implement or to implement well, echoing the concerns of some critics, this was not ubiquitous. Indeed we found that the range and depth of teachers’ use of differentiated teaching practices was enhanced by strong and committed leadership. It was also supported by quality professional learning, which contributed to staff buy-in and a school-wide culture of teacher collaboration, as well as supporting the quality and frequency of teacher implementation of differentiation.

We also found great diffusion in how differentiation was conceptualised making it difficult to produce clear findings about whether differentiation works. Despite this, the reviewed studies that examined the impact of differentiation consistent with our definition generally indicated that it typically produced improvements in student learning when compared to regular practice, with some suggestion that this may be even greater in more disadvantaged schools. There was little evidence to support criticisms that differentiation waters down the curriculum or lowers expectations and no studies advocating for the creation of individual lesson plans for individual students. Given the number of studies and participants that are represented in our review, this effectively dispels these criticisms as myth.

The diversity of focus and methodological approaches across the 34 studies, however, prevents a structured comparison of findings and therefore weakens the evidential basis to make stronger claims of either differentiation’s effectiveness or indeed its ineffectiveness. In particular, strong claims were hampered by the fact that:

• Half the 34 studies were conducted in the United States and most in the elementary (primary) school phase with very few studies focusing on secondary schools.
• Survey and case study designs were dominant, as was research of influences on teacher practice.
• Only a small group of studies focused on differentiation’s impact on student outcomes and these typically only examined specific elements of differentiation or in specific academic domains, such as science or reading.
• The majority of studies were undermined by methodological weaknesses—such as a tendency to rely on convenience samples and to use weak forms of survey methodology, as well as to attempt to determine the impact of differentiation using only student achievement scores—validating some concerns about the state of the research on differentiation.
• Poor design weakened the strength of the overall findings because of the incommensurability between the measures used by participants from different schools and districts, and the incommensurability of practices across cases.
• Although there were some studies that investigated the impact of differentiation using rigorous procedures, the majority of research was compromised by the use of small sample sizes and researcher-developed instruments with no clear theoretical or empirical foundation.
• A lack of transparency due to poor reporting and very little cross-referencing between studies led to the majority ‘remaking the wheel’ rather than working together to create a coherent evidence-base.

Recommendations

Our research suggests that research on differentiation can and should improve, if the understanding of the practice is itself to improve.

Far too many studies are conducted without a coherent and theoretically informed definition to guide the development of instruments or to provide an appropriate lens through which to analyse the data collected. Having now read a vast number of articles, each claiming to be about differentiation, we observe that new research on this topic must build from and improve on previous studies. This is important to avoid researchers approaching the topic with the assumption that there is common agreement as to what differentiation is, or proposing their own new definition.

To achieve this, we believe future research on differentiation could:

• clearly define differentiation as a range of evidence-based practices that teachers can use to meet the needs of all learners in heterogeneous classrooms
• investigate the planning and enactment of these practices in both primary and secondary general education settings
• use rigorous mixed-method research designs capable of assessing the adequacy of those practices for meeting the full range of individual learning needs, whilst determining the effect on students’ engagement, educational experiences, and academic outcomes; and
• monitor implementation fidelity and the impact on teachers’ work.

We see our paper and our considered definition of differentiation grounded in prior research as a starting point to build useful evidence on differentiation for schools and teachers in Australia. If we are to use differentiation to meet the needs of students with and without disabilities in our schools, teachers need to be on the same page and confident in the evidence behind the practices they are using.

For those who want more, here is our full paper: A scoping review of 20 years of research on differentiation: investigating conceptualisation, characteristics, and methods used

Professor Linda Graham is Director of The Centre for Inclusive Education (C4IE) at Queensland University of Technology (QUT). Her research investigates the role of education policy and schooling practices in the development of disruptive student behaviour and the improvement of responses to children with language, learning and behavioural difficulties.

Dr Kate de Bruin is a senior lecturer in inclusion and disability in the Faculty of Education at Monash University. She has taught in secondary school and higher education for two decades. Her research focuses on inclusive education in policy and practice, examining system, school and classroom practices that are supported by evidence, and that promote quality and equity for all students, with specific attention to students with a disability.

Dr Carly Lassig is a Lecturer in The Centre for Inclusive Education (C4IE) at QUT with a passion for social justice, equity and inclusion. Her research and teaching interests include: inclusive education, disability, differentiation, Universal Design for Learning, gifted education, and creativity. Carly’s PhD, “Perceiving and pursuing novelty: A grounded theory of adolescent creativity” investigated young people’s experiences of creativity within and beyond the school environment. Carly’s background is as a primary and middle years teacher, having taught nationally and internationally.

Dr Ilektra Spandagou is an Associate Professor of Inclusive Education at The University of Sydney. Ilektra worked as a special education teacher and completed her PhD at the University of Sheffield in the area of inclusive education. She worked as a researcher at the University of Sheffield,and as a lecturer at the University of Athens and the University of Thessaly, Greece before moving to The University of Sydney. Her research interests include disability, classroom diversity, and curriculum differentiation.