Hattie conducted meta-analytical reviews that take into account about 1000 meta-analyzes of factors affecting student achievement and include approximately 60,000 studies, some of the studies are based on up to five million students and the overall meta-analysis covers a total of 245 million students [7,8]. These studies reveal that the individual characteristics of the student, and particularly their intellectual capacity and motivation, are among the variables that contribute most to academic performance.
