I had the same question before I became a student. Now that I have had some lessons, I can provide you with my own explanations for having always provided five stars.

First, there's no indication whether the rating is anonymous. After a lesson, the student is asked to rate the lesson out of five stars and to write a summary. The summary is public and the teacher is able to respond. This suggests that the teacher may also be able to see the rating provided.

Because I never knew whether the teacher could see my rating, I was loathe to provide less than five stars. The only certain outcome of providing, say, three stars is that I annoy my teacher. The teacher may then feel disinclined to answer follow-up questions I might have.

There is also the knowledge that everyone else seems to provide five stars. If I am then the sole person who provides three stars, that identifies me as an ungrateful, hard-to-please student.

My final reason was modesty. After a particular lesson with a teacher, I was quite annoyed and decided that I needed to find a new teacher. I was then asked to provide a rating for the lesson. My first instinct was to provide a low rating, because I had been unhappy with our final few lessons. Yet I recognized that maybe the weakness was with me as a student. I didn't want to be petty, so I provided a five star rating and found a new teacher.

These reasons are all based on not knowing whether the ratings are anonymous. (Even if they are, a new teacher with few students will be able to discern a student's most-recent rating.) To my mind, the ratings are useless, so too are the comments. It's a public back-slapping exercise that achieves nothing. Yet maybe the public cheering conveys a sense of community and mutual support. As a feedback system the star rating is useless, as a flag it may have some value.

I wouldn't pay it much mind. It's a beta test, so the grading or even the whole idea could change in the future.

As far as I can tell, as long as a teacher/tutor turns up and teaches a lesson, and the student is happy enough, then it's five stars. If a problem is reported (eg. the lesson couldn't happen because of an absence or technical issues), then that might affect the overall rating.

I can't recall, but I think extremely lazy or poor teachers - always missing lessons, unhappy students, inappropriate behaviour - have their accounts suspended or deleted. It's written somewhere in the teacher's agreement or TOS.  Honestly, I'd say this is extremely rare anyway, and the community here has a high standard. :)

For me, the best way to gauge a teacher's ability is to read the profile, watch the video and read any feedback from other students.

Ho Alister. The rating is anonymous but it's true that it's tricky to give bad rating if you're one of the first student!

Thank you Peachy and Alister! That's a really interesting explanation. Usually, I think that a star rating works pretty well but it seems not to be the case here. So I guess the best way to know if a teacher is good is to check whether he did several lessons with the same student :)

Uh,I'm a new comer here.And I don't even know how many stars I have!  In my opinion,people here are well educated.At least everyone can speak several languages.Because I'm from China,most of us just speak Chinese and speak English occassionally. Most of us take little time to learn a third language. So,that's why I'm here—to learn something and make more friends.  I can really learn much through people here.  Their learning spirit is very precious for me.