How can I effectively challenge a final grade? I'm enrolled in an honours philosophy program (taking premed prereqs and maths as electives), going into my fourth year. I had a 3.9 until today when I got my first B. I made a point of kicking the crap out of the final essay; Nevertheless, the TA crushed me on it. I received less than 60%.  

I'm applying to med school in the fall. Given the way that the schools that I'm going to apply to weight the grades of applicants, that B is going to be considerably damaging to my application. 

There are two phases in the univeristy's process for appealing a grade. 


Talk to the professor
Appeal to the university for an independent evaluation.


To the best of my knowledge, independent reviews are usually kangaroo processes that just confirm the original decision. Fortunately, the university's process isn't the only way to resolve the problem. The TA, the professor, and the department head all could change the result. 

I don't suspect the TA will change his opinion. 

The professor is good friends with the TA. Generally, people tend to defend their friends when someone accuses them of making a mistake. Ultimately, if I appeal to the professor, no matter how I approach it, the appeal will amount to an accusation that her friend made a mistake. Accordingly, I don't believe that I would succeed if I were to do that. Moreover, if I were to appeal to the professor, she would need to justify her decision, and by doing so, would become convinced her TA got it right. 

Accordingly, I see three ways I could go about it: 


Write the professor (I can't meet with her, I'm out of province this week, and need to contact her within seven days) and hope it works out (I'm pretty confident nothing will happen). 
Write the professor and, using all the tact I can muster, gently allude to the escalation process, and the fact that it would just be easier to give my essay a fair shake. I saw a lawyer use the 'it's just easier to say yes' approach with a judge once. It worked surprisingly well. Nevertheless, it's kind of a jackass thing to do, and could backfire if my tact fails me. 
Approach the department head: I'm in his good book. I first got to know him after he emailed me to talk about pursuing work in philosophical research. It was out of the blue, so I figure that's some sign that he'd like to see that happen. (I'd like to help solve some of the conceptual problems that predominate psychiatry.) He and I have spent about ~20 hours working one on one to solve some philosophical problems. I've done well in his classes. So, he knows I generally do good work and he seems to want to ensure things work out well. I suspect that he would doubt that the TA could justify giving me &lt;60% on the essay. Perhaps he might suggest some way to fix the problem, or might offer an alternative if I can't fix it (e.g. 'Try this, and if it doesn't work, come back and talk to me.')


How can I effectively challenge the grade that I've received?
I would go through the process set out by your university. Talk to the professor first. You don't have to phrase it as an attack on the TA. Just tell the professor that you feel the grade was too harsh, and you would like him or her to review it. If you feel that the professor doesn't fairly address your concerns, then take it to the department head, and perhaps ultimately to an independent review committee. Typically, in order to get a grade changed by a committee, you will have to show that there was an error in grading your paper or that your paper was not graded consistently with the other papers. If the TA graded everyone's papers harshly, then there's not much of a basis for a complaint. As was pointed out in the comments, if you go to the department head before you talk to the professor, the professor will likely be annoyed at being blindsided by an issue they were unaware of. Also faculty are given broad leeway in grading their classes as long as it is done consistently. Unless there is an egregious mistake and the faculty is uncooperative, it is not the department head's place to interfere, and they most likely will just leave it to the professor.