Why Hindi generation needs a deliberate benchmark
A Hindi model can achieve a respectable automatic score while still producing awkward, overly Sanskritised, repetitive, or factually unsafe text. Benchmarking should therefore measure more than word overlap. It should tell you whether a model follows prompts, preserves meaning, uses natural Hindi, handles code-mixed inputs, and behaves consistently across domains and user groups.
This matters for Indian products such as education assistants, customer support, public-service interfaces, search tools, and content workflows. Before selecting a model, define the task and its acceptable failure modes. A short answer-generation system, for example, should be judged differently from a translation or summarisation model. For broader dataset and evaluation design, use the Indian language LLM benchmark datasets guide as a companion reference.
Build a Hindi evaluation set
Start with a fixed, versioned test set rather than evaluating on prompts written ad hoc during development. Include examples that reflect how people in India actually write and speak:
- Standard Devanagari Hindi: Formal and conversational prompts with varied sentence length.
- Code-mixed Hindi: Hindi written with English product names, technical terms, and Roman-script phrases.
- Roman Hindi: Inputs such as “aap kaise ho” if your product accepts them.
- Regional variation: Examples influenced by North Indian vocabulary and everyday usage, without treating one dialect as the only valid Hindi.
- Domains: Education, finance, healthcare, government services, retail, and customer support.
- Difficulty cases: Negation, numbers, dates, names, lists, instructions, and multi-turn context.
Each record should contain an id, prompt, optional context, one or more acceptable references, and metadata such as domain and task type. Keep a private test split for final comparisons. Never tune prompts or decoding settings against that split.
Multiple references are particularly useful for open-ended Hindi generation. A correct answer may use different word order or vocabulary from the reference, and a single reference can penalise valid output unfairly. Record whether references were written by native Hindi speakers and whether they allow code-mixing.
Install the evaluation stack
Use a pinned environment so results remain reproducible across model updates:
python -m venv .venv
source .venv/bin/activate
pip install "transformers" "datasets" "evaluate" "sacrebleu" "rouge-score" "bert-score" pandasHugging Face Evaluate provides a common interface for loading metrics, but it does not contain one universal text-generation-quality metric. Load each metric explicitly and check its documentation, version, inputs, and language assumptions before interpreting results.
import evaluate
bleu = evaluate.load("sacrebleu")
rouge = evaluate.load("rouge")
bertscore = evaluate.load("bertscore")For a production benchmark, save the Python version, package lockfile, model revision, tokenizer revision, decoding parameters, dataset hash, and hardware details. These records make score changes explainable.
Generate outputs under controlled settings
Use the same prompts and decoding configuration for every candidate model. Avoid comparing one model with greedy decoding against another model with a high temperature.
from transformers import pipeline
generator = pipeline(
"text-generation",
model="your-hindi-capable-model",
tokenizer="your-hindi-capable-model",
device_map="auto",
)
prompts = [
"ग्राहक को देरी के लिए विनम्र उत्तर लिखें।",
"जल संरक्षण के तीन व्यावहारिक उपाय बताइए।",
]
outputs = generator(
prompts,
max_new_tokens=96,
do_sample=False,
return_full_text=False,
)
predictions = [item[0]["generated_text"] for item in outputs]Use max_new_tokens rather than an unrestricted max_length when comparing responses of different prompt lengths. For creative generation, run several fixed seeds and report the average and spread. Also test deterministic decoding separately; it often reveals repetition and instruction-following problems more clearly.
Select metrics that match the task
Reference-based metrics
SacreBLEU is useful for translation-like tasks where close lexical correspondence is expected. ROUGE can help with summarisation and key-content recall. BERTScore may capture semantic similarity better than exact n-gram overlap, but its multilingual model choice affects results substantially.
bleu_result = bleu.compute(
predictions=predictions,
references=[[ref] for ref in references],
)
rouge_result = rouge.compute(
predictions=predictions,
references=references,
use_stemmer=False,
)
bert_result = bertscore.compute(
predictions=predictions,
references=references,
lang="hi",
)Do not compare scores from incompatible preprocessing pipelines. Hindi punctuation, Unicode normalisation, danda characters (।), whitespace, nukta forms, and numeral conventions can materially change lexical metrics. Store both raw and normalised text, and document every transformation.
Task and quality checks
Automatic metrics should be supplemented with checks for:
- Prompt adherence: Does the response follow format, length, and language instructions?
- Meaning preservation: Are facts, entities, numbers, and negations retained?
- Fluency: Is the Hindi grammatical and natural to a native reader?
- Relevance: Does the answer address the request without filler?
- Safety: Does it avoid harmful, discriminatory, or unsupported advice?
- Repetition: Does it loop phrases or recycle templates?
For semantic or factual evaluation, an LLM judge can be useful as a triage tool, but calibrate it against human ratings and do not treat it as ground truth. A useful rubric scores each dimension from 1 to 5 and includes written examples for every score.
Human evaluation for Hindi and code-mixing
Recruit at least two independent Hindi-fluent reviewers for a representative sample. If the product serves a particular region or audience, include reviewers familiar with that context. Blind the model identity, randomise output order, and measure reviewer agreement.
Ask reviewers to mark specific error categories rather than giving only an overall score:
- unnatural or translated-sounding Hindi;
- incorrect honorifics or register;
- wrong names, numbers, dates, or units;
- inappropriate English substitution;
- unsupported claims or hallucinations;
- failure to answer the prompt;
- offensive or culturally unsuitable wording.
Report the mean score, percentage of critical failures, and confidence intervals where possible. A model with a slightly lower BLEU score but fewer factual and instruction-following failures may be the better production choice.
Analyse results by slice, not only by average
Create a results table for every example with the model revision, prompt category, metric scores, reviewer labels, latency, and output length. Then break down performance by task, script, domain, and difficulty. Aggregate scores can hide serious weaknesses in healthcare prompts, Roman Hindi, or long-context inputs.
Compare candidate models using the same test set and report a baseline. A small open model may be attractive for cost and latency; the open-source small language models for Hindi guide can help shortlist candidates. For a broader cross-language view, see this practical framework for benchmarking multilingual LLMs in India.
Make the benchmark operational
Run the evaluation in CI whenever you change model weights, prompts, retrieval, tokenisation, or safety filters. Set regression thresholds for critical slices, not just one overall score. For example, block a release if factual-number accuracy falls or if unsafe-response rates rise, even when average ROUGE improves.
Keep a small error notebook with the prompt, output, expected behaviour, reviewer explanation, and fix attempted. Re-run old failures after each change. For teams evaluating Telugu, Sanskrit, or other Indic systems alongside Hindi, the NLP benchmarking guide for Telugu and Sanskrit offers a useful comparison point.
A practical reporting template
Every benchmark report should state:
- dataset size, source, licence, and train/test separation;
- task definitions and reference-creation process;
- model and tokenizer revisions;
- decoding parameters and random seeds;
- normalisation and metric versions;
- automatic scores by slice;
- human rubric, reviewer profile, and agreement;
- critical error rates, latency, and cost per request;
- known limitations and next evaluation priorities.
This approach turns Hugging Face Evaluate from a quick score generator into a repeatable decision system. It helps Indian builders choose models based on the quality that users experience—not merely the metric that looks best in a leaderboard.