Hattie's Research Design

Hattie set out to find out about the impact of different factors on student learning. He looked at the evidence from over 800 meta-analyses which encompassed 52,637 studies. These recorded the impact of different factors from the home, student, teacher, teacher strategies, curriculum and school as effect sizes. He found the average effect size for each contribution (resulting in 146,142 effect sizes) and ranked these according to their impact. He estimated that his study included approximately 236 million students. Hattie developed a scale (or barometer) to help interpret the effect sizes and compare the different contributions. He argued that it is important to determine what works best rather than what works. His barometer included negative effects (-0.20-0.00), developmental effects (0.00-0.15), typical teacher effects (0.15-0.40) and a zone of desired effects (0.40+). Hattie found that in a typical year the average teacher would have an effect size of between 0.15 and 0.40. He therefore argued that it was important to look for innovations with effect sizes greater than 0.40 which he termed the hinge point. Interventions above the 0.40 hinge mark would have an impact that was greater than that of an average teacher.