org.dkpro.statistics.agreement.distance

Class OrdinalDistanceFunction

java.lang.Object

org.dkpro.statistics.agreement.distance.OrdinalDistanceFunction

All Implemented Interfaces:

IDistanceFunction

public class OrdinalDistanceFunction
extends Object
implements IDistanceFunction

Implementation of the IDistanceFunction interface for scoring the distance between ordinal-scaled categories. That is to say, categories represent ranks, such as the values on a Likert scale. A typical example is FULLY AGREE, RATHER AGREE, UNDECIDED, RATHER DISAGREE, FULLY DISAGREE. Note that one cannot easily say that the difference between FULLY AGREE and RATHER AGREE is equal. The intuition of the ordinal distance is function is rather to count the number ranks in between a pair of given ranks. Consider the example by Krippendorff (1980): 10 units are assigned the ranks 1, 2, 3, 3, 4, 4, 4, 4, 5, 10. Then intuitively, the difference should be much smaller between 1 and 3 then between 3 and 5. In the case of uniform frequencies of the ranks (e.g., 1, 1, 2, 2, 3, 3, 4, 4), the ordinal distance function equals the IntervalDistanceFunction. Mathematically, the ordinal scale only allows for the equality and comparison operations, but prohibits addition and multiplication. The distance function assumes the ranks to be of type integer. For other category types, the distance function falls back to a NominalDistanceFunction.

References:

• Krippendorff, K.: Content Analysis: An Introduction to Its Methodology. Beverly Hills, CA: Sage Publications, 1980.

Author:

Christian M. Meyer

See Also:

IDistanceFunction

Constructor Summary

Constructors

Constructor and Description
OrdinalDistanceFunction()

Method Summary

Modifier and Type	Method and Description
double	measureDistance(IAnnotationStudy study, Object category1, Object category2) Returns a distance value for the given pair of categories used within the given annotation study.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OrdinalDistanceFunction

public OrdinalDistanceFunction()

Method Detail

measureDistance

public double measureDistance(IAnnotationStudy study,
                              Object category1,
                              Object category2)

Description copied from interface: IDistanceFunction

Returns a distance value for the given pair of categories used within the given annotation study. Normally, the measure should return a distance of 0 if, and only if, the two categories are equal and a positive number otherwise.

Specified by:

measureDistance in interface IDistanceFunction