Model Description
A LoRA fine-tuned version of Phi-3.5-mini-instruct for marking
GCSE, AS-Level and A-Level Mathematics answers against official
mark schemes from AQA, Edexcel and OCR.
Built by QuantOsimo — an AI-powered
Maths and Science tutoring platform for UK students KS2 to A-Level.
This is v1.1 — trained without 2023-2024 papers to allow
genuine held-out evaluation. See v1 for the full 2018-2025
trained model.
Evaluation Results — Genuine Held-out
Evaluated on 50 questions from 2023-2024 papers
not seen during training.
- Attempted correctly: 43/50 (86%)
- Wrong or unreadable input: 7/50 (14%)
By Exam Board
Table with columns: Board, Score| Board | Score |
|---|
| AQA | 82% (14/17) |
| Edexcel | 100% (17/17) |
| OCR | 75% (12/16) |
By Level
Table with columns: Level, Score| Level | Score |
|---|
| GCSE | 88% (30/34) |
| AS-Level | 100% (10/10) |
| A-Level | 50% (3/6) |
Notes
- v1 in-distribution score: 88% vs v1.1 held-out: 86%
Only 2% drop — model generalises well to unseen papers
- 5 of 7 wrong answers had garbled PDF input text
(unreadable questions — not model errors)
- OCR lower score reflects PDF extraction quality issues
- A-Level based on only 6 questions — too small to be conclusive
- Edexcel and AS-Level: perfect scores across all questions
Training Details
- Base model: microsoft/Phi-3.5-mini-instruct
- Method: LoRA (r=16, alpha=16)
- Epochs: 3
- Training examples: 4,066
- Years: 2018-2022 and 2025
(2023-2024 held out for evaluation)
- Boards: AQA, Edexcel, OCR
- Levels: GCSE (Foundation and Higher), AS-Level, A-Level
- Subject: Mathematics
- Training time: 116 minutes on Kaggle T4 x2
Training Data
Fine-tuned on 4,066 examples extracted from official past
examination papers and mark schemes published by AQA, Pearson
Edexcel and OCR for GCSE, AS-Level and A-Level Mathematics,
covering the years 2018-2022 and 2025.
Training data is not published due to exam board copyright.
A sample of 100 examples is available at:
uk-gcse-alevel-maths-markschemes-2018-2025
Intended Use
- Automated marking of student answers in EdTech platforms
- Research into automated assessment
- Educational AI development
Limitations
- Only trained on Mathematics
- UK curriculum only (AQA, Edexcel, OCR)
- Some OCR papers have garbled PDF extraction affecting results
- A-Level evaluation based on small sample (6 questions)
How to Use
from transformers import AutoModelForCausalLM, AutoTokenizerfrom peft import PeftModelimport torch base_model = "microsoft/Phi-3.5-mini-instruct"model = AutoModelForCausalLM.from_pretrained( base_model, torch_dtype=torch.float16, device_map="auto", attn_implementation="eager")model = PeftModel.from_pretrained( model, "Osam-2025/quantosimo-maths-marking-v1.1")tokenizer = AutoTokenizer.from_pretrained(base_model)
Citation
@misc{osagiede2026quantosimomarking, author = {Osagiede, Samuel}, title = {QuantOsimo Maths Marking Model v1.1}, year = {2026}, url = {https://huggingface.co/Osam-2025/quantosimo-maths-marking-v1.1}}