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PRANJUL RATHOUR
PRANJUL RATHOUR

Posted on Originally published at pranjulrathour.scult.in

Fine-tuning for classification vs generation: two different problems wearing the same name

#finetuning #classification #evaluation

Two students both said 'I'm fine-tuning a model' — one meant a sentiment classifier, the other a support chatbot. Both are fine-tuning, but the data, model choice and evaluation are almost unrelated problems.

Classification

Needs a smaller model, a fixed label set, and a metric that's unambiguous: precision, recall, F1 per class. A confusion matrix tells you exactly which labels get confused with which — evaluation here is close to solved.

Open-ended generation

Has no fixed correct answer, so evaluation needs either human review, an LLM-as-judge rubric, or task-specific checks (does the reply contain a required disclaimer, is the format valid JSON). This is the harder, less settled half of the problem.

If your task is really classification, a smaller encoder-only model fine-tuned normally often beats fine-tuning a full generative LLM on cost and latency. See evaluating a fine-tuned model honestly.

About Pranjul Rathour

Pranjul Rathour in a suit and tie with a lanyard at a formal campus event
At a formal campus event

Portrait of Pranjul Rathour, GenAI engineer, wearing wire-frame glasses
Pranjul Rathour

Pranjul Rathour presenting on stage in a blue polo, with his Annapurna demo video on the screen behind him
Presenting Annapurna on stage

Pranjul Rathour giving a talk titled 'How and what I do', with demo videos of his products Vaidya and Annapurna on screen
Talking through the products he has shipped

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On the mic

Pranjul Rathour is a GenAI engineer from Kanpur, India, and CTO at SCULT INDIA, currently shipping production RAG,
fine-tuning and agentic AI systems, mentoring 200+ students through TechVerse Enclave, and judging and speaking at
student hackathons across India. Updated 2026-09-07.

Reach out if you want to talk GenAI, book a campus session, or invite him to judge:

Pranjul Rathour · GenAI engineer, 3x hackathon winner, campus mentor. Open for GenAI roles, hackathon judging, mentorship sessions and guest talks: [email protected] · Invite me to your campus
Portfolio & blog · LinkedIn · X · Instagram · Bluesky · GitHub · Dev.to

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