Multi-Variant LLM A/B Testing

Evaluate & Benchmark

Multi-Variant LLM A/B Testing

Statistical A/B/n testing for 3+ model variants with ANOVA, Bonferroni correction, and sub-millisecond routing overhead.

The problem

Testing 3+ model variants at once usually breaks either statistical rigor or user experience consistency.

  • The same user gets routed to a different model variant every time they refresh.
  • With three variants running, nobody trusts the winner because the math wasn't done right.
  • A/B testing tooling built for buttons doesn't know what to do with LLM outputs.

What NEO built

NEO built deterministic MD5-hash routing for consistent bucketing, async queue-based logging, and ANOVA with Bonferroni-corrected pairwise tests to find the winning variant.

Deterministic routingANOVAStatistical testing

The result

<0.5ms routing overhead

Runs at <0.5ms routing overhead while sustaining 1000+ req/s and delivering full statistical analysis in about 2 seconds.

Beyond A/B: Building a Multi-Variant LLM Testing Framework with Statistical Rigor

From the blog · 8 min

Beyond A/B: Building a Multi-Variant LLM Testing Framework with Statistical Rigor

NEO built a production-ready A/B/n testing framework for LLMs that supports 3+ model variants, uses ANOVA and Bonferroni correction for statistical analysis, and adds under 0.5ms routing overhead.

Try this in your workspace

Paste this into NEO chat to kick off the same workflow on your own data.

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Set up an A/B/n test across these 3 model variants with consistent user bucketing and proper statistical correction, and tell me which one actually wins.

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