Hattie’s Effect Size is a way to measure the impact of various educational strategies on student learning, based on a large body of research. An effect size of 0.4 or higher is the "hinge point," meaning strategies above this level significantly impact learning. Below 0.4, the effects are considered less impactful. The strategies being highlighted are considered top influences. Hattie’s research emphasizes that teachers should focus on strategies with higher effect sizes to ensure the best learning outcomes. For example, rather than focusing too much on class size (0.21), prioritize practices like formative assessments (0.68) that have a larger impact.
The document below can be opened to scroll through the full scope of Hattie's research. The domain on the right side may be insightful when selecting strategies to implement for learning. The link takes you to the Visible Learning site that provides the origin of the document information.