With children with severe disabilities, the progress that students make is sometimes so slight, so minimal in terms of the gains, that they could be easily missed. In actuality, perhaps the only way that gains can be observed is via the systematic taking of instructional data. You see, a teacher may have 13 students in a classroom with perhaps 8 IEP objectives each. If the teacher is not taking data on the student, they she is claiming to be able to monitor 104 (8x23) objectives, objectives that may only evidence tiny steps of progress, in her head. This is ridiculous! It is not possible. It is only through systematic collection of data on student performance that a teacher has any idea of how a student is performing on instructional tasks.
The other day, I was in a classroom with a student teacher. She is doing a good job as student teachers go. She had been taking data on student performance in a relatively regular, systematic fashion. I asked her, "How are your students performing on their tasks?" She replied, "Fine." As I observed, I would have to agree with her, as my general impression was they were doing fine as well. However, we randomly took 3 skills that students were working on and graphed the data. The first student's data indicated that she had met criterion about a month ago. That is, the level of performance for the skill that was considered mastery in the objective had been met...a month ago. So the teacher had continued to work on the skill with the student, even though she had met the objective. Because she hadn't graphed the data, she didn't know. The second data set we graphed indicated that the student had made no progress over the 5 weeks of instruction delivered thus far. So the teacher had naively been providing an instructional strategy for 5 weeks with no benefit to the student relative to the objective as stated. The third data set demonstrated that the instructional program was working and the student was making good progress! Probably in another month the student would reach criterion.
The point of this is not to criticize the student teacher, but to say that understanding student performance is not something that can be easily seen unless one is made aware of how the student is actually performing via the taking of data. To say, "I don't take any data" is tantamount to saying, "I really don't care whether or not the student is progressing."
Some teachers will say, "I can either teach or take data" which is a silly thing to say as the only way to teach students with severe disabilities is to take data. So I would argue that if you are not taking data, you are doing something, but whatever it is it is not educating the students in the manner they need to be educated.
An additional problem is the extensive problem of teachers working in classrooms for students with disabilities and doing nothing. It breaks my heart when I see teachers that I have trained whom I know, know what they should be doing but have succombed to the pressure of the environment, the pressure to be mediocre from districts, and regress to the mean of NOT educating their students but rather babysitting them...all the while collecting their paycheck as if they actually were educating them.
Teachers who are doing a good job, however, literally take your breath away when they show you their data, when the indicate that they know exactly where a student is functioning educationally. But they are too often rare.
A basic premise I learned when I was being trained as a teacher was...
Every child can benefit from a public school education
I think I would now restate that to say that every child can benefit from a public school education if their teacher actually cares enough to educate them and be aware of whether they actually are benefitting from the education as it is being delivered.