How to Evaluate LLM Performance
Set up comprehensive evaluation for your AI system measuring quality, safety, and reliability.
What You'll Learn
You cannot improve what you do not measure, and this is especially true for AI applications where output quality can vary significantly across inputs, model versions, and prompt changes. LLM evaluation is the practice of systematically measuring your AI system's quality, safety, and reliability using a combination of automated metrics, LLM-as-judge techniques, and human assessment. Without proper evaluation, you are flying blind, unable to tell whether a prompt change improved or degraded your system, whether a new model version is better for your use case, or whether your guardrails are actually catching harmful outputs. The evaluation landscape has matured rapidly with tools like LangSmith, Braintrust, and custom evaluation frameworks making it practical to build comprehensive evaluation into your development workflow. This guide teaches you how to define evaluation criteria, build test datasets, implement automated evaluation, conduct human evaluation, and integrate evaluation into your CI/CD pipeline for continuous quality assurance.
Step 1: Define evaluation criteria
Identify what matters — accuracy, helpfulness, safety, consistency, latency, and domain-specific metrics.
Step 2: Build an evaluation dataset
Create 50-200 test cases with expected outputs covering normal cases, edge cases, and adversarial inputs.
Step 3: Implement automated evaluation
Use LLM-as-judge, exact match, BLEU/ROUGE scores, and custom metrics for automated quality assessment.
Step 4: Run human evaluation
Conduct human rating studies for subjective quality, comparing outputs side-by-side across model versions.
Step 5: Set up continuous evaluation
Integrate evaluation into your CI/CD pipeline to catch quality regressions before deployment.
Conclusion
LLM evaluation is the foundation of reliable AI product development. The essential steps are: define clear evaluation criteria tied to your use case, build a diverse test dataset covering normal cases, edge cases, and adversarial inputs, implement automated evaluation using LLM-as-judge and custom metrics, validate with periodic human review, and integrate evaluation into your CI/CD pipeline. Investing in evaluation early prevents the quality regressions that erode user trust over time. ShipSquad builds comprehensive evaluation into every AI system we ship. If you need help setting up evaluation for your AI product, start your mission at shipsquad.ai.
Frequently Asked Questions
How many test cases do I need?▾
Start with 50-100 high-quality test cases covering key scenarios. Expand to 200+ as you identify new failure modes.
Can AI evaluate AI?▾
LLM-as-judge works well for many evaluations, achieving 80-90% agreement with human raters. Use it for scale but validate with periodic human review.
What metrics matter most?▾
Task completion rate and user satisfaction are the most important. Latency and cost matter for production. Safety metrics are non-negotiable.