What Effect Does a Bad Teacher Have on Students?

Teachers who are not effective in the classroom have a have a significant effect on the learning process — and not in a good way. According to a study conducted jointly by economists at Harvard and Columbia universities, the overall effect of a bad teacher is similar to fourth-grade students missing 40 percent of the school year. Other studies indicate that a good teacher can lead to gains in the learning process that will have lasting effects. Poor teaching over the course of several years can cause students to be unprepared for college attendance, if they even have any desire to pursue a degree.

More on the impact of teachers:

According to a study conducted by the Tennessee Value-Added Assessment System in the United States, students who are taught by poor teachers for three consecutive school years exhibit an average achievement gain of 29 percent. By contrast, students who have competent teachers for three years in a row exhibit an average achievement gain of 83 percent.
Encountering a good teacher in the fourth grade increases the chances of students eventually attending college by 1.25 percent, and it helps reduce the incidence of teen pregnancy by roughly the same percentage.
Students who have good teachers consistently from the fourth grade onward are likely to earn a higher incomes per year during their adult years than students who struggle through with below-average teachers. According to the Harvard study, the quality of teaching can lead to earning an extra $25,000 US Dollars during a student’s lifetime.