Natural Language Processing · TEE · papers
Q5b · Classification label structures
2024-02-12 · re-exam · recovered AI paper
Previous examination · complete worked answers
Question. Compare binary, multiclass and multilabel supervised text classification with examples. [10 marks]
Answer
| Type | Allowed output | Example | Typical output rule |
|---|---|---|---|
| Binary | One of two labels | positive OR negative review | One sigmoid or two-class softmax |
| Multiclass | Exactly one of several labels | sport OR business OR science | Softmax over mutually exclusive classes |
| Multilabel | Zero, one or several labels | Article tagged technology AND finance | Independent sigmoid per label |
Multiclass and multilabel differ in whether labels may coexist, not merely in the number of labels. A loss and evaluation measure must match the task.