Title
Structural Quality Metrics as Indicators of the Long Method Bad Smell: An Empirical Study
Abstract
Empirical evidence has pointed out that Extract Method refactorings are among the most commonly applied refactorings by software developers. The identification of Long Method code smells and the ranking of the associated refactoring opportunities is largely based on the use of metrics, primarily with measures of cohesion, size and coupling. Despite the relevance of these proper-ties to the presence of large, complex and non-cohesive pieces of code, the empirical validation of these metrics has exhibited relatively low accuracy (max precision: 66%) regarding their predictive power for long methods or extract method opportunities. In this work we perform an empirical validation of the ability of cohesion, coupling and size metrics to predict the existence and the intensity of long method occurrences. According to the statistical analysis, the existence and the intensity of the Long Method smell can be effectively predicted by two size (LoC and NoLV), two coupling (MPC and RFC), and four cohesion (LCOM1, LCOM2, Coh, and CC) metrics. Furthermore, the integration of these metrics into a multiple logistic regression model can predict whether a method should be refactored with a precision of 89% and a recall of 91%. The model yields suggestions whose ranking is strongly correlated to the ranking based on the effect of the corresponding refactorings on source code (correl. coef. 0.520). The results are discussed by providing interpretations and implications for research and practice.
Year
DOI
Venue
2018
10.1109/SEAA.2018.00046
2018 44th Euromicro Conference on Software Engineering and Advanced Applications (SEAA)
Keywords
Field
DocType
long method,coupling,cohesion,size,case study
Cohesion (chemistry),Data mining,Ranking,Predictive power,Empirical evidence,Computer science,Source code,Real-time computing,Code refactoring,Empirical research,Method Code
Conference
ISSN
ISBN
Citations 
1089-6503
978-1-5386-7384-3
0
PageRank 
References 
Authors
0.34
0
6
Name
Order
Citations
PageRank
Sofia Charalampidou1756.01
Elvira-Maria Arvanitou2317.37
Apostolos Ampatzoglou333441.24
Paris Avgeriou41956139.94
Alexander Chatzigeorgiou579060.13
Ioannis Stamelos6124391.67