How to build a labeled dataset for NLP
Most custom NLP models need labeled examples: emails tagged with the right category, sentences with entities marked or reviews scored for sentiment. The quality of those labels sets the ceiling for model accuracy. Rushed or inconsistent labeling produces models that learn the confusion rather than the task.
Start with a clear labeling guide written with the people who handle this text today. Define each category or entity with examples and counterexamples, and explain how to treat ambiguous cases. Have two people label the same sample independently and compare results; disagreements reveal unclear definitions that need fixing before scaling up.
Large language models can speed this up by pre-labeling text for humans to correct, which is far faster than labeling from scratch. Active learning, where the model asks for labels on the examples it is least sure about, focuses human effort where it improves accuracy most.


