How to react to a student who provides very critical comments about your teaching in a student evaluation survey? I am a teacher in an institute and I teach English as a foreign language to students in an 8_week session. At the end of each session, the students are required to give their opinion about the class and the teacher.

One of my students who attended all the classes and I corrected at least 20 writings for her has written something horrible and of course has ruined my rating by saying: "What we learn depends on the teacher. I recommend teacher X, but I absolutely and strongly reject this teacher who does not know anything about teaching (meaning me)." She has also written her name on top of the paper.

She never, ever, complained about my teaching method during the time we had class together and this sudden unfair comparison has gone on my nerve. I have taken a photo of what she has written about me and it is in my mind to email it to her and ask for her explanation. 

I have signed no contract with that institute and I have received no teacher training courses. I have teaching experiences somewhere else and that was why they invited me to teach. But their unfair system of evaluation at the end of each session will definitely have effects on my payment and if it continues like this, I will no longer be able to continue teaching there.

I am REALLy thinking so deeply about what I could have done wrong. My last session assessment was 20% higher than an old teacher who is teaching there for 3 years. Another serious problem I have with this issue is the "comparison". I teach Reading and Writing and my colleague teaches Listening and Speaking. Of course, I have never met the other teacher. But, he has read this bad comment about me. Why should I lose my face in front of a colleague, because of an "unfair" judgement?

Is it good to react like this, or I should keep silent about her unfair judgement?
You said,


  this sudden unfair comparison has gone on my nerve


It sounds like this negative feedback has provoked some strong emotion in you, and understandably so. 

But asking for an explanation is not likely to be helpful at this point. This isn't a constructive comment that can potentially lead you to improve your teaching - it's just an insult. Students take out all kinds of frustration in their teaching evaluations. If you ask a frustrated student to explain a comment they made (most likely) out of frustration, you are unlikely to gain anything constructive. The most likely outcome is that she'll unload more frustration on you.

The best reaction to this kind of feedback (assuming it's an isolated incident, and the rest of your feedback was reasonable) is to re-read the positive feedback you've received, remind yourself that you're a dedicated teacher who works hard to help your students, and put the non-constructive feedback out of your mind.

If this is an isolated incident, I wouldn't worry about its effect on your ranking within your institution. All instructors will occasionally receive some negative reviews, no matter how good they are at teaching.