Evidence shows that ‘collective teacher efficacy’ is the strongest predictor of student achievement1. This means that teachers’ self belief in their own capacity to positively affect students determines whether students learn. But the tough reality is that most teachers do not feel empowered to make a difference.

Maths Pathway combines highly effective evidence-based practices2 with tools and strategies to create a holistic model that supports teachers.

Many of our components are included in the Visible Learning research, which synthesises findings from 1,500 meta-analyses of 90,000 studies involving 300 million students, into what works best in education3.

Maths Pathway is not a substitute or replacement for teachers, but a powerful set of components that, when put into the hands of educators, magnifies their impact in the classroom.

Effect size is a way of evaluating the impact of an educational approach or intervention. It is calculated by dividing the difference in the means of a control group and a ‘treatment group’, by the pooled standard deviation of the samples. For example, an effect size of 1.0 tells us that the means of the two groups differ by a standard deviation, representing what’s considered a large effect size. The average effect size in educational research is 0.4. Effect sizes less than 0.15 are considered small, and interventions with effects greater than 0.4 fall within the zone of desired effects.

About effect size

Although the use of effect size has produced much conversation and innovation in education, like with all academic research, interpretation should be balanced. According to Coe, care must be taken with respect to effect size for educational programs and interventions. The word ‘effect’ connotes or implies ‘causality’ when in many cases there is an identified relationship and should be used only when it can be justified. We must also be careful when comparing or aggregating effect sizes when there are: 1. different operationalisations of the same outcome, 2. different treatments, 3. different levels of the same treatment and 4. measures derived from different populations4.


  1. Waack, S 2018, Collective teacher efficacy according to John Hattie, link
  2. Hattie, J 2009 Visible learning: a synthesis of over 800 meta-analyses relating to achievement, Routledge, London, New York, link
  3. Hattie, J 2009 Visible learning: a synthesis of over 800 meta-analyses relating to achievement, Routledge, London, New York, link
  4. Coe, R 2002, ‘It’s the Effect Size, Stupid: What effect size is and why it is important School of Education’, University of Durham, presented at the Annual Conference of the
    British Educational Research Association, University of Exeter, England

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Maths Pathway combines evidence-based practices in a holistic model that supports teachers to deliver differentiated teaching and achieve greater student growth in the classroom.

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Impact Report 2019

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