12. Core NLP Task Patterns
Connect architectures to real business outcomes.
01 Learning objectives
By the end of this module, you should be able to explain the concept in plain language, connect it to a use case, and recognize when it is — and is not — appropriate.
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Objective 1
Recognize task/output shapes.
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Objective 2
Choose metrics appropriate to the task.
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Objective 3
Understand model-family choices.
02 Classification
Input: document/sentence
Output: one or more labels
Examples: complaint routing, fraud narrative classification, intent detection.
03 Token classification / NER
Input: token sequence
Output: label per token
Examples: customer name, account number, organization, date, location.
04 Semantic similarity
Input: two texts or query + document corpus
Output: similarity score / ranked results
Examples: duplicate complaints, knowledge retrieval.
05 Generation
Input: prompt/context
Output: generated token sequence
Examples: summaries, explanations, draft responses.
06 Pitfalls and nuances
These are the mistakes most likely to create a wrong mental model or a weak implementation.
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Pitfall 1
Using the same metric for every NLP task.
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Pitfall 2
Ignoring calibration when probabilities trigger automated business decisions.
07 Checkpoint questions
Try answering these without looking back at the module. If the explanation is clear in your own words, you are ready to continue.
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Check 1
Which task produces one label per token?
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Check 2
Which task powers vector-based retrieval?