Disadvantages: high demands on teachers and great pressure on teachers.
The theoretical basis of "27 1 rule";
An interesting phenomenon of "27 1" in the class: in each class, the students' performance is roughly as follows: 20% children have excellent grades and are active in learning; 70% of the students' performance is average; In addition, 10% of children are students with learning difficulties. Among them, 70% of the students with medium grades show two directional development trends, one is to strive to develop upwards towards 20%, and the other is to slowly slide below 10%. The goal of education should be to promote 10% children to improve their learning efficiency, and to maximize 70% students to flock to the ranks of top students.
The difference of teachers' teaching level also shows the law of "27 1": 20% are leading teachers, 70% are excellent teachers, and the remaining 10% are teachers who need to be improved as a whole. The main goal of the construction of school teachers should be to find effective ways to make 20% leading teachers give full play to their roles, promote the development of 70% teachers to 20% groups through team efforts, and influence the transformation of 10% teachers to 70%.
To improve the quality of teaching, we must first grasp every 70% part of the "27 1 law", that is, 70% of the backbone trained by teachers' professional growth should grasp 70% of the mainstream students in the class, and return 70% of the 45 minutes to the students, so as to improve classroom efficiency through teacher-student interaction, students' autonomy and group inquiry.