URI: http://www.qualityml.org/1.0/metrics/MatthewsCorrelationCoefficient
Name: Matthews Correlation Coefficient
Alternative names: MCC

The Matthews correlation coefficient is used in machine learning as a measure of the quality of binary (two-class) classifications. It takes into account true and false positives and negatives and is generally regarded as a balanced measure which can be used even if the classes are of very different sizes. The MCC is in essence a correlation coefficient between the observed and predicted binary classifications; it returns a value between −1 and +1. A coefficient of +1 represents a perfect prediction, 0 no better than random prediction and −1 indicates total disagreement between prediction and observation. The statistic is also known as the phi coefficient.

Parameters: actual categories
Source: GeoViQua
Categories: Thematic accuracy
Further information: http://en.wikipedia.org/wiki/Matthews_correlation_coefficient
XML schema:
<schema xmlns:qml="http://www.qualityml.org/1.0" 
xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.qualityml.org/1.0" 
elementFormDefault="qualified" attributeFormDefault="unqualified">
<import namespace="http://www.uncertml.org/2.0" schemaLocation="../../uncertml/2.0/uncertml.xsd"/>

	<element name="AreaUnderROCCurve" type="qml:ContinuousValuesSummaryStatisticType" substitutionGroup="un:AbstractSummaryStatistic"/>
XML example:
JSON example:
API example:
Value constraints: categories: any string
counts: any positive natural number