- When they get to know us, it may be difficult to know how we are, and how they should make it work for us, says Deliah Johansson Al-Faisal, who has changed mentor several times during middle school.

That teacher turnover is a problem for students, parents and schools alike has been described many times in individual cases.

For the first time, SVT can now show how extensive teacher turnover is.

One in four teachers changes jobs every year.

Half work for a maximum of three years at the same school.

- It affects weak students the most, because they have a special need to get a predictable and safe education, says Karin Lindqvist, investigator at the Swedish Schools Inspectorate.

May lead to incorrect grading

According to Karin Lindqvist, it is clear that teacher changes have consequences for students.

Anxiety in the classroom, slowed learning and difficulty in making a fair assessment of students' competence are some examples.

In some cases, it can even lead to incorrect grading.

- We have seen examples of teachers perhaps not having such good documentation about what they have done earlier in the year, and that a new teacher comes in and has quite a bit to go on when it comes to grading.

- Then maybe you go on what the student had for grades in previous years, or you might look very much at certain individual documents, says Karin Lindqvist.

"Must create attractive workplaces"

Another thing that suffers from frequent teacher changes is the students' relationship with the adults in the school.

Something that Yosya's Mengisteab Haile at Boliden School recognizes herself in.

- I have had a bit of a hard time trusting a teacher, but if I trust a teacher, it is good for me and for it, he says.

SVT has been in contact with teachers all over the country, who have told why they have chosen to resign from their workplace.

The most common cause, according to those we spoke to, is a poor work environment.

Many also state that they change jobs to increase their salary.

- There is a shortage of teachers and it is the teachers' labor market.

Since we have that situation, the employer also needs to create really attractive workplaces so that the teachers want to stay, says Karin Lindqvist, investigator at the Swedish Schools Inspectorate.