Ulchik Dulchik

Hi guys, has anyone ever managed to get their grade or essay/dissertation mark changed upon appeal? I am about to graduate from SOAS MSc Development Studies. I was on track for a Distinction, but my tutor awarded me a 69% for my dissertation. I am trying to reason with him and get it looked at again or considered for 'rounding-off' of the grade to 70% (which is what they do in the Anthropology department), but he is not budging and actually being a little aggressive, to the extent that now I am worried he will be less positive on my PhD references. I am sure he would not do so, but in any case, I want to do everything in my power to have the grade changed, since I fundamentally disagree with the reasons for which I was penalised. Does anyone have any experience of this or stories to share or advise on what I should/could do?