The following is a summary of pages 170-171 of John Hattie´s Visible Learning.
Mastery learning´s claim is that all children can learn when provided with clear explanations of what it means to “master” the material being taught. Features of Mastery Learning include: appropriate learning conditions in the classroom, such as high levels of cooperation between classmates; high levels of teacher feedback that is both frequent and specific by using diagnostic formative tests; and the regular correction of mistakes students make along their learning path. The important variable in mastery learning is the time required to reach the levels of attainment. The material is divided into small learning units, each with their own objectives and assessment. Each unit is preceded by brief diagnostic tests, which provide information to identify gaps and strengths. No student proceeds to new material until prior or more basic prerequisite material is mastered.
Kulik, Kulik, and Bangert-Drowns (1990) found mastery learning programs had a positive effect on examination performance of students, raising examination performance by about half a standard deviation, especially for low-aptitude students. Mastery programs had positive effects on student attitudes towards course content and instruction, but increased student time spent on instructional tasks.