Rare category
A rare category is a class or entity represented by substantially fewer observations than other categories in a dataset.
Machine Learning for Tabular Data: XGBoost, Deep Learning, and AI
A rare class is a target category represented by a small proportion of observations in a dataset.
- How it is used
- Flags infrequent categorical values before modeling so they can be treated as a source of potential overfitting.
- How deep it goes
- Defines rarity, explains its overfitting risk, and recommends aggregation while deferring implementation details to later methods.
- Examples
- Uses infrequently occurring labels, domain-guided category aggregation, target encoding, and embeddings as concrete treatments.
- What you can do after
- Apply domain knowledge to aggregate similar rare labels and distinguish that remedy from encodings for high-cardinality features.
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Outlier Detection in Python
A minority class is a class containing substantially fewer observations than the majority class or classes in a classification dataset.
- How it is used
- Uses imbalanced classification datasets to evaluate outlier detectors against labeled rare classes.
- How deep it goes
- Defines rarity, explains down-sampling and evaluation trade-offs, but stops short of specifying a detector.
- Examples
- Uses KDD Cup network attacks and artificially down-sampled classes as rare-category examples.
- What you can do after
- Evaluate outlier detectors with labeled imbalanced datasets while recognizing masking and project-specific suitability.
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Delivering Machine Learning Projects: From design to deployment
A rare entity is an infrequently occurring subject, case, or category represented in a data set.
- How it is used
- Audits data assets for sampling distortion, missing cases, and misleading operational conclusions.
- How deep it goes
- Explains over-representation, omission, and representativeness risks through a concrete case, without specifying remediation algorithms.
- Examples
- Uses criminal databases in which serious offenders are recorded more often than petty offenders.
- What you can do after
- Diagnose whether recorded rare cases can support representative profiles and safe operational interventions.
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Related concepts
- upsamplingconfigured by · Upsampling is a process that increases the number, density, or spatial or temporal resolution of samples or values in a dataset or representation by adding, duplicating, or estimating them.
- fraudincludes · Fraud is intentional deception or unauthorized activity undertaken to obtain an improper benefit or cause another party a loss.
- domain knowledgeused by · Domain knowledge is specialized understanding of the concepts, facts, practices, relationships, and constraints of a particular subject area.
- anomalykind of · An anomaly is an observation, behavior, or state that deviates from an expected or typical pattern or condition.
- rare wordcontrasts with · A rare word is a word that occurs substantially less often than other words in a reference text collection.
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