740f02measure17 1 an evaluation of the mood set of object-oriented software metrics harrison,...

740f02measure17 1

An Evaluation of the MOOD Set of Object-Oriented Software Metrics

Harrison, Counsell and Nithi

IEEE Trans on Soft Eng

June 1998

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Criteria for Valid Metrics

1. Must allow different entities to be distinguished

2. Must obey representation condition 3. Each unit of attribute contributing to a

valid metric is equivalent 4. Different entities can have the same

attribute value

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types of measurement

direct– does not depend on other measures

indirect– involves one or more other measures– e.g. density

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Indirect metrics

1. Explicitly defined model 2. Model must be dimensionally consistent 3. No unexpected discontinuities 4. Units and scale types must be correct

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MHF definition

Summation over all methods in all classes of 1 minus the V(M) divided by the total number of methods

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mim

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MVMHF

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11

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Model for MHF?

What would be a good abstraction?

Is there a well-understood Empirical Relationship?

Scale Type?

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Validation – MHF/AHF

1. Must allow different entities to be distinguished

2. Must obey representation condition 3. Each unit of attribute contributing to a

valid metric is equivalent 4. Different entities can have the same

attribute value

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Indirect Validation – MHF/AHF

1. Explicitly defined model

2. Model must be dimensionally consistent

3. No unexpected discontinuities 4. Units and scale types must be correct

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Inheritance Factor

Md(Ci) = number of methods declared in a class i

Mi(Ci) = number of methods inherited (and not overridden)

in a class iMa(Ci) = Md(Ci) + Mi(C i) = number of methods that can

be invoked in association with class i 

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CMMIF

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1

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Model for MIF?

What would be a good abstraction?

Is there a well-understood Empirical Relationship?

Scale Type?

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Validation – MIF/AIF

1. Must allow different entities to be distinguished

2. Must obey representation condition 3. Each unit of attribute contributing to a

valid metric is equivalent 4. Different entities can have the same

attribute value

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Indirect Validation – MIF/AIF

1. Explicitly defined model

2. Model must be dimensionally consistent

3. No unexpected discontinuities 4. Units and scale types must be correct

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Coupling Factor

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Model for CF?

What would be a good abstraction?

Is there a well-understood Empirical Relationship?

Scale Type?

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Validation – CF

1. Must allow different entities to be distinguished

2. Must obey representation condition 3. Each unit of attribute contributing to a

valid metric is equivalent 4. Different entities can have the same

attribute value

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Indirect Validation - CF

1. Explicitly defined model

2. Model must be dimensionally consistent

3. No unexpected discontinuities 4. Units and scale types must be correct

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Polymorphism FactorLet Mo(Ci) be the number of overriding methods in class i.

Let Mn(Ci) be the number of new methods in class i.

 Let DC(Ci) be the number of descendants of class i.

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CMPF

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Model for PF?

What would be a good abstraction?

Is there a well-understood Empirical Relationship?

Scale Type?

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Validation – PF

1. Must allow different entities to be distinguished

2. Must obey representation condition 3. Each unit of attribute contributing to a

valid metric is equivalent 4. Different entities can have the same

attribute value

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Indirect Validation - PF

1. Explicitly defined model

2. Model must be dimensionally consistent

3. No unexpected discontinuities 4. Units and scale types must be correct