Notes from the work.
What we learn running annotation, evaluation and live review for AI teams.
How to Measure Data Annotation Quality: Inter-Annotator Agreement, Gold Sets, and Review (2026 Guide)
How to measure annotation quality with inter annotator agreement, gold sets and review reliability, and how to catch reviewer drift.
You Don't Have a Labeling Problem. You Have a Disagreement Problem.
Two careful annotators will disagree on your hardest data. That gap, not careless mistakes, is what most annotation quality problems are made of.