The local high school where my sons go has a school wide policy of grading. 90% of the grade for EVERY class is based on test scores.

Homework and participation is only 10%. This has proven disastrous for several of my sons. Students are able to retake some tests.
All of the boys in high school have an IEP. Even with an IEP, we have not been able to get this policy modified enough for them to be real successful. For my developmentally disabled sons, we are able to get them support in special ed classes. For the ones with learning disabilities, it is not so easy. J3 and C have gotten it together and are actually doing pretty good.
V is still struggling. He has 4 F's, 1 D, and 1 A. On the surface, one would think that V is failing. I printed off his grades and reviewed them. He has mostly A's and B's on homework and participation. The test scores are what is hurting his grades. V can retake most tests, but has to go to the teacher to schedule the retake. V is very shy. He won't go to the teachers. I know that...the teacher of record knows it...V knows it. So...V is failing. Personally, I think the system is failing him.
I spoke to a "little bird" who offered a different approach. We all know that V will quit school as soon as he can legally do it or gets thrown out. He has lost hope. Today, I spent some time talking to him about home school again. We talked about "throwing out" mainstream education and working towards a GED. I talked with him about taking a college class and getting a part time job. V actually was "excited" about what I was talking about.
No final decisions have been made...but he seems relieved tonight. I asked him how he felt, and he said that "like weight had been lifted off his shoulders". Tonight, he is much more animated.
Thanks "little bird" for giving me a different perspective and letting me vent.