AI Glossary
Perplexity
What is Perplexity?
A metric used to evaluate language model quality — roughly measuring how surprised the model is by a given text. Lower perplexity indicates the model assigns higher probability to the observed text, suggesting better language modeling. Perplexity is a useful intrinsic metric but does not directly measure real-world task performance.
Example in practice
A researcher comparing two language models on medical text would use perplexity to measure which model better predicts clinical language — a low perplexity model has a stronger statistical grasp of medical terminology.
Learn more
See Perplexity applied in a professional context through this free course.
AI Fundamentals for Professionals →