John Hattie is a researcher in education. His interests include performance indicators, measurement models, and teaching and learning evaluation. He became known to a wider audience with his two books, Visible Learning and Visible Learning for Teachers. Visible Learning synthesizes more than 800 meta-studies covering more than 80 million students. According to Hattie, Visible Learning is the result of 30 years of research about what works best for learning in schools. He also serves as a technical advisor for i-Ready as well as chair of the Board of the Australian Institute for Teachers and School Leaders. In March 2023, he released Visible Learning: The Sequel: A Synthesis of Over 2,100 Meta-Analyses Relating to Achievement.