High-quality English teachers have a positive long-term impact on the performance of students in other subjects, according to a study conducted by Professor Susanna Loeb and her colleagues at Stanford University.
For the purposes of the study, a “good” English teacher was defined as one who generated above average increases in the test scores of students.
The conclusions were based on the performance of 700,000 students in New York City, ranging from third through to eighth standard, from 2003-10.
Read more at Stanford University