Something that is very important for teachers to know about their students is their prior knowledge about the topic that they are going to be teaching. There are many different ways to assess this, it can be as simple as asking a question and seeing if they students know anything about it at the beginning of class or more complex like giving students a test to see where they stand.
I think that pre-assessing is an important part of teaching, you are able to see if there is something that everyone struggles with so you spend more time on it or something that everyone gets so you can do a quick review. When teachers don’t pre-assess you don’t know exactly know where to start.
I think that it is vital for teachers to pre-assess, in class we were told how a teacher gave a test to their students for pre-assessment. They made it very clear to the students that this wasn’t for grades, they wanted to see what they know and that the “final” test was going to be something similar to this but with different numbers. After this test they found that one student got a hundred. If they teacher hadn’t pre-assessed then this students would have been unchallenged, because they choose to pre-assess they were able to modify the work so that it was challenging to the student. I think that is a great example of why diagnostic assessment is beneficial for both the students and the teacher.