I have just received my GCSE results today. My dream is to apply to Oxford to study Physics in the year commencing 2026. This is what I have wanted for years, but until now I have had no actual exams to base my plans on. Now that I have my GCSE results, I was hoping to be able to start making a prediction about my odds of getting into Oxford, and whether it is actually feasible. I have applied to study Physics, Maths, Further Maths and Computer Science at Sixth Form, and I understand that the minimum A-Level entry requirements for Physics at Oxford are "A*AA to include Mathematics and Physics. The A* must be in Mathematics, Physics or Further Mathematics."
I was reading the Oxford Physics "Admissions Report" from 2023, and came across the "R-score", described as "the principal determinant for shortlisting". The formula for calculating this before interviews is:
R-score pre-interview = PAT mark + 10 x cGCSE
and after the interviews is:
Post-Interview R-score = (PAT mark out of 100) + 10 x cGCSE + 2 x (Interviews out of 100).
I have looked into what "cGCSE" ('Contextualised GCSE') refers to, and it appears to be my GCSE grades relative to other people in my year group at school? Oxford themself describe it as "the number of standard deviations the applicant is away from their ‘expected’ number of A*/9/8 grades and was typically be in the range −3 to +3, expressed to 2 decimal places".
Essentially, I understand what a cGCSE score represents, but I want to know actually how to calculate it myself, so I can start making predictions. Oxford's explanation gives me a decent crack at being able to work it out, except I don't know exactly what they mean by "expected" number of 9s/8s. Does each school have an 'expected 9/8 value'? If so, how do I find out what my school's is?
I apologise for what has turned into quite a long rant, this is just something I am quite invested in, so I would really appreciate it if anyone could help me out here.