When I was a pupil I was part of the age cohort that took part in the very first PISA test. The results that were released two years or so later were devastating for education in Germany. Out of all the countries that took part, we were pretty close to last. In the following few years many new policies were implemented that radically changed how pupils were taught. But more importantly a social change happened, a change that teachers in other countries already know too well, but was totally new to us. The teachers were blamed for a pupil’s failure.
Economists have spent quite some time researching the impact of teachers on student achievement. As in my previous blog posts, figuring this out is not as easy as one might think. The problem is that there is no way to run an experiment to see what a pupil’s achievement would be if they would be allocated their teacher at random, because in practice, teachers and pupils aren’t matched at random or anything close to it.
In my previous blog post I listed, what is known in the field as, the education production function, which states that a pupil’s achievement is the result of
1. Aspects of the pupil him or herself, such as ‘natural ability or talent’, motivation, etc
2. His or her family support and the socialisation he or she receives at home
3. The school he or she attends which comprises the behaviour of the
a. School leaders
b. Teacher
c. Pupil’s peers.
Teachers and pupils are not allocated to one another by random because there are many choices involved. Parents choose the schools they send their pupils to, within schools, school leaders allocate teachers to classes. Teachers may also negotiate with them which clases they are allocated to. Aspects of the school also play a role; the school’s geographical location or public/private school status might work as signals to teachers so that generally schools will not be able to choose from the same pool of applicants.
So if you can’t do experiments, then you need to have really good data so you can isolate the effect of the teacher on a student’s achievement. In order to do that you need to track both students and their teachers over time. I will not delve into the statistical methods how you can do this here – if you are interested please feel free to read the second chapter of my PhD thesis for some references.
The US and the UK are two countries who keep a lot of data on their teachers and students. Research from these countries shows that in the US the effect of teachers on student achievement is approximately 10 percent and approximately 15 percent in the UK. Their research also shows that teachers of maths and science seem to be slightly more important than for student’s progress in reading achievement.
Sadly these findings are basically unknown among the wider public. It also means that what happens outside the teacher’s classroom is more important, especially the role of the family the students grow up in is not to be underestimated. So please feel free to spread the word that blaming the teacher for a student’s academic failure won’t help much.