A Tool-Based Perspective on Software Code Maintainability Metrics: A Systematic Literature Review

Table 6

Metrics found in the selected set of primary studies, with the number of mentions and score higher or equal to 2.

Metric suite	Metric	Mentioned by	TOT	Score
—	Avg CC, average cyclomatic complexity	[5, 54]	2	2
—	CA, afferent coupling	[5, 21]	2	2
—	CC, McCabe’s cyclomatic complexity	[14, 24, 51], S13, [6, 16, 32, 45, 48], [23, 29, 31, 35, 47]	14	12
—	CE, efferent coupling	[5, 21, 25]	3	3
—	CHANGE, number of lines changed in the class	[5, 25, 26, 43]	4	4
Chidamber and Kemerer	CBO, coupling between objects	[5, 14, 15, 21, 25–27, 32, 44], [20, 23, 28, 29, 35, 36, 39, 47, 50]	18	16
Chidamber and Kemerer	DIT, depth of inheritance tree	[5, 14, 26, 43], S13, [20, 21, 27, 32], [23, 28, 29, 35, 39, 47]	15	13
Chidamber and Kemerer	LCOM, lack of cohesion in methods	[5, 14, 26, 43], S13, [20, 27, 28, 32], [23, 36, 39, 46, 47]	14	12
Chidamber and Kemerer	NOC, number of children	[5, 14, 26, 43], S13, [20, 27, 32, 39], [23, 29, 35, 47]	13	11
Chidamber and Kemerer	RFC, response for class	[5, 14, 15, 19, 21, 26, 27, 43, 44], [20, 23, 29, 32, 39, 46, 47, 50]	17	15
Chidamber and Kemerer	WMC, weighted methods per class	[5, 26, 43], S13, [16, 20, 21, 27, 32], [23, 29, 39, 47]	13	11
—	CLOC, comment lines of code	[5, 24, 25], S13, [28, 35]	6	6
—	Code-to-comment ratio	[14, 15]	2	2
—	CSA, class size (attributes)	[5, 25]	2	2
—	CSO, class size (operations)	[5, 25]	2	2
—	CSOA, class size (operations+attributes)	[5, 25]	2	2
—	DAM, data access metric (card metric)	[21, 47]	2	2
Halstead	Halstead bugs (B)	[5, 14, 23, 25, 47, 48]	6	4
Halstead	Halstead difficulty (D)	[5, 14, 23, 25, 45, 47, 48, 51]	8	6
Halstead	Halstead effort (E)	[5, 14, 23, 25, 45, 47, 48, 51]	8	6
Halstead	Halstead length (N)	[5, 14, 23–25, 45, 47, 48, 51]	9	7
Halstead	Halstead vocabulary (n)	[5, 14, 23, 25, 45, 47, 48, 51]	8	6
Halstead	Halstead volume (V)	[5, 14, 25, 51], S13, [6, 23, 45, 48], [47]	10	8
—	JLOC, JavaDoc lines of code	[5, 25, 28]	3	3
—	LCOM2, lack of cohesion of methods	[21, 29, 35]	3	3
—	LCOM3, lack of cohesion of methods	[21, 35]	2	2
Li and Henry (L&H)	DAC	[39, 43]	2	2
Li and Henry (L&H)	MPC, message passing coupling	[25, 39, 43, 46]	4	4
—	LOC, lines of code	[14, 15, 21, 24–26, 44, 51], [6, 23, 31, 32, 35, 50]	15	11
—	MI, maintainability index	[6, 14, 25, 30, 44, 51]	6	4
—	MOA, measure of aggregation	[21, 28]	2	2
—	NOAC, number of operations added	[5, 25]	2	2
—	NOM, number of methods	[26, 28, 31, 43]	4	4
—	NPM, number of public methods	[5, 21, 28, 29]	4	4
—	Number of classes (including nested classes, interfaces, enums, and annotations)	[31, 35]	2	2
—	Number of commands	[5, 25]	2	2
—	Number of files	[31, 33]	2	2
—	Number of queries	[5, 25]	2	2
—	PDcy, number of package dependencies	[5, 25]	2	2
SM, structural measures	TCC, tight class cohesion	S13, [35]	2	2
—	STAT, number of statements	[5, 25, 31, 35]	4	4
—	WMC, McCabe’s weighted method count	[14, 15, 25, 28, 36, 38, 50]	7	7
—	WMCU, McCabe’s weighted method count-unweighted	[15, 50]	2	2