Now I'm not debating that individual test scores reflect a teacher's ability. What I am debating for is the occasion when a majority of a class has low or failed test scores. A teacher can be a very well articulated and all around kind person yet not have the raw ability to get their points across. In this case the students unless having taken it upon themselves to learn the subject will not fully understand the concepts. This is not because the teacher does not have well meant intentions or because the students have an inability to learn, it is just a teacher's overall skill. There are some subjects that are just hard for everyone in general but in these cases all that is needed is someone that can connect and understand a students needs and concerns to help the student succeed.
I believe that test scores do not reflect how good teachers are. A teacher has to teach a large classroom with many diverse learners, students with sometimes a large gap of abilities. Some students with disabilities do not have the motivation or home support to do well in school, so their test scores might be lower. That should not affect an evaluation of a teacher. There should be other factors besides test scores that tell you how good a teacher is.
Teachers can assist students in acquiring the skill and knowledge necessary to successfully take tests. They cannot, however, force students to take ownership of their education. It is the students' acceptance of that accountability that assigns value to what the teacher is doing in the classroom, and, not the collective test scores of all students, some of who may understand the concept of educational ownership and some who don't.