/ department of mathematics and computer science

SLOC and defect prediction

Where innovation starts

By no means:A study on aggregatingsoftware metrics

Bogdan Vasilescu

Alexander SerebrenikMark van den Brand

2

May 20, 2011

3/5

/ department of mathematics and computer science

Methodology

Issue tracker

r3780 | kataka | 2003-04-12 00:43:24 +0200 (za, 12 apr 2003) | 2 linesChanged paths: M /argouml/model/uml/modelmanagement/ModelManagementHelper.java M /argouml/uml/ui/foundation/core/ActionSetParameterType.java

Fixed issue 1544------------------------------------------------------------------------r3769 | alexb | 2003-04-11 11:27:55 +0200 (vr, 11 apr 2003) | 4 linesChanged paths: M /argouml/uml/ui/foundation/core/PropPanelClass.java M /argouml/uml/ui/foundation/core/PropPanelInterface.java

fix for

Issue number: 1736

Version control system

Software system

10

2

11

4/5

/ department of mathematics and computer science

Correlation between SLOC and defects

ArgoUML Adempiere Mogwai#Java classes 1230 4047 2310#Packages 94 152 365#Bugs mapped 39 163 38

mean 0.023 (7) 0.392 (3) 0.197 (2)median -0.142 (8) 0.311 (4) 0.129 (7)sum 0.313 (1) 0.510 (1) 0.151 (3)IGini 0.267 (3) 0.225 (5) 0.134 (6)ITheil 0.269 (2) 0.185 (6) 0.135 (5)IAtkinson 0.245 (4) 0.168 (7) 0.138 (4)IHoover 0.240 (5) 0.113 (8) 0.122 (8)IKolm 0.144 (6) 0.412 (2) 0.204 (1)

5/5

/ department of mathematics and computer science

The aggregation techniqueinfluences the correlation.

Mean, median are inconsistent.

6/5

/ department of mathematics and computer science

Emerging trend

7/5

/ department of mathematics and computer science

Inequality indices

Econometrics: measure/explain the inequality of income or wealth.

8/5

/ department of mathematics and computer science

Inequality indices

Econometrics: measure/explain the inequality of income or wealth.

Software metrics and econometric variables have distributions withsimilar shapes.

Household income in Ilocos, the Phillippines (1998)

Income

Fre

quen

cy

0 500000 1000000 1500000 2000000 2500000

020

040

060

0

hibernate−3.6.0−beta4: org.hibernate.criterion

SLOC

Fre

quen

cy0 50 100 150 200 250 300

05

1525

35

Inequality in quality 6= low quality !

8/5

/ department of mathematics and computer science

Inequality indices

Econometrics: measure/explain the inequality of income or wealth.

Software metrics and econometric variables have distributions withsimilar shapes.

Household income in Ilocos, the Phillippines (1998)

Income

Fre

quen

cy

0 500000 1000000 1500000 2000000 2500000

020

040

060

0

hibernate−3.6.0−beta4: org.hibernate.criterion

SLOC

Fre

quen

cy0 50 100 150 200 250 300

05

1525

35

Inequality in quality 6= low quality !

9/5

/ department of mathematics and computer science

Inequality indices and software metrics

9/5

/ department of mathematics and computer science

Inequality indices and software metrics

Decomposable indices (partition the population into MECE groups):I which partition provides the best explanation for the inequality?

10/5

/ department of mathematics and computer science

Traceability via decomposability

Which individuals (classes in package) contribute to 80% of theinequality (of SLOC)?

Which class contributes the most to the inequality?