Definition
AI evaluation (commonly called "evals") is the practice of systematically testing AI system outputs against predefined benchmarks, quality criteria, and task-specific metrics. Unlike traditional software testing, where inputs map deterministically to expected outputs, AI evals must account for the probabilistic nature of model outputs, the subjective quality of generated content, and the wide variety of inputs an AI system may encounter in production.
Evals typically combine automated metrics (accuracy, relevance scores, safety classifications) with human evaluation (quality ratings, preference comparisons, error categorization). A comprehensive eval suite covers the happy path, edge cases, adversarial inputs, and safety-critical scenarios, providing a multidimensional picture of how the AI system performs across the conditions it will face in production.
Why It Matters for Product Managers
Evals are the foundation of data-driven AI product development. Without them, product teams are flying blind -- making decisions about model selection, prompt design, and feature readiness based on anecdotes and demos rather than systematic evidence. PMs who invest in comprehensive evals can confidently answer questions like "Is this model better than the alternative?" and "Is this feature ready to ship?"
Evals also protect against silent regressions. When a model provider updates their API, when prompts are modified, or when retrieval systems change, evals immediately surface any quality degradation. This is especially important because AI failures are often subtle -- the system still produces coherent output, but the quality, accuracy, or safety has silently deteriorated.
How It Works in Practice
Common Pitfalls
Related Concepts
AI evals are essential for validating AI Safety requirements and measuring AI Alignment with intended behaviors. They support Responsible AI governance by providing evidence of fairness and quality. Evals specifically target failure modes like Hallucination and are complemented by Grounding techniques for factual accuracy.