The case for evaluating LLM apps: why reading a few answers fools everyone, offline versus online evaluation, the eval mindset, and what quality dimensions to measure — then build your first end-to-end eval harness for Docent.
Welcome to Why Evaluation Matters, the opening module of the course. Before you can measure an LLM app well, you have to understand why measuring it at all is harder — and more necessary — than it looks. This module makes that case and gives you the vocabulary and mindset the rest of the course builds on.
You’ll start with the “looks fine” trap: read a few of Docent’s answers, decide it works, and then watch it fail on a question you didn’t happen to check. From there you’ll learn the difference between offline evaluation (on datasets, before you ship) and online evaluation (on real traffic, after you ship), the mindset that replaces gut feel with repeatable metrics, and the quality dimensions — correctness, faithfulness, relevance, format, cost, latency — that a serious eval has to cover. The module closes with a guided project where you build a small but real evaluation harness for Docent, end to end.
Start with Lesson 1, and let Docent fool you before you learn not to be fooled.
Complete all 5 lessons to finish the Why Evaluation Matters module.