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.