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Anomaly score

An anomaly score is a numerical measure of how anomalous an observation or event is relative to a reference or expected pattern.

How 2 Manning books explain it

Outlier Detection in Python

A numerical estimate of how unusual an item is relative to a specified reference group.

How it is used
Ranks records by estimated unusualness relative to a reference group, leaving any binary threshold to the application.
How deep it goes
Works through statistical, neighbor, histogram, and cluster-relative scoring, then examines score direction, thresholds, evaluation, and combination.
Examples
Uses fund segments, baseball nearest-neighbor scores, speech-data histograms, and FPOF and KDE score distributions.
What you can do after
Apply it via detector scores to rank investigation candidates, assess ranking quality, and choose thresholds cautiously.

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Azure Security

Anomaly scoring is a web application firewall evaluation method that assigns a cumulative score to detected request anomalies to determine whether traffic is blocked.

How it is used
Determines whether Azure WAF on Application Gateway blocks requests that match managed rules.
How deep it goes
Explains severity values, cumulative addition, and the prevention threshold, but does not detail individual rule logic.
Examples
Uses critical, error, warning, and notice scores plus a two-rule total of 3 and 2.
What you can do after
Operate/configure prevention behavior by interpreting rule severities and predicting when requests will be blocked.

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Related concepts

These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.