1 Background
2 Related work
3 Unit test case metrics
4 Empirical study
4.1 Selected case studies
Systems | (1) | (2) | (3) | (4) | (5) | (6) | (7) |
---|---|---|---|---|---|---|---|
ANT
| 713 | 64062 | 111 | 8121 | 15.60% | 27.50% | 46.12% |
JFC
| 496 | 68312 | 226 | 20657 | 45.60% | 77.80% | 38.89% |
JODA
| 225 | 31591 | 77 | 46702 | 34.22% | 55.80% | 264.17% |
LUCENE
| 659 | 56902 | 114 | 21997 | 17.30% | 38.80% | 99.54% |
POI
| 1539 | 136005 | 404 | 41610 | 26.25% | 43.20% | 70.82% |
IVY
| 610 | 50080 | 95 | 12531 | 15.57% | 36.00% | 69.44% |
4.2 Research methodology and data collection
4.3 Understanding the underlying dimensions captured by the unit test case metrics
4.3.1 ANT
F1 | F2 | F3 | F4 | F5 | |
---|---|---|---|---|---|
Variability (%)
| 46.6 | 33.737 | 12.049 | 4.235 | 3.379 |
% Cumulated
| 46.6 | 80.337 | 92.386 | 96.621 | 100 |
ANT (Correlation)
|
ANT (Square-cosine)
| ||||
F1
|
F2
|
F1
|
F2
| ||
TINVOK
| 0.013 | 0.843 | 0 | 0.71 | |
TDATA
| 0.899 | −0.002 | 0.809 | 0 | |
TASSERT
| 0.934 | 0.102 | 0.873 | 0.01 | |
TLOC
| 0.775 | 0.515 | 0.601 | 0.265 | |
TNOO
| 0.217 | 0.837 | 0.047 | 0.701 |
4.3.2 JFC
F1 | F2 | F3 | F4 | F5 | |
---|---|---|---|---|---|
Variability (%)
| 50.152 | 39.124 | 6.923 | 2.771 | 1.029 |
% Cumulated
| 50.15 | 89.28 | 96.2 | 98.97 | 100 |
JFC (Correlation)
|
JFC (Square cosine)
| ||||
F1
|
F2
|
F1
|
F2
| ||
TINVOK
| 0.837 | 0.358 | 0.701 | 0.129 | |
TDATA
| 0.209 | 0.951 | 0.044 | 0.905 | |
TASSERT
| 0.647 | 0.694 | 0.419 | 0.481 | |
TLOC
| 0.746 | 0.634 | 0.556 | 0.402 | |
TNOO
| 0.887 | 0.197 | 0.787 | 0.039 |
4.3.3 JODA
F1 | F2 | F3 | F4 | F5 | |
---|---|---|---|---|---|
Variability (%)
| 93.366 | 2.949 | 2.454 | 0.996 | 0.235 |
% Cumulated
| 93.366 | 96.315 | 98.769 | 99.765 | 100 |
JODA (Correlation)
|
JODA (Square cosine)
| ||||
F1
|
F1
| ||||
TINVOK
| 0.952 | 0.906 | |||
TDATA
| 0.953 | 0.908 | |||
TASSERT
| 0.955 | 0.911 | |||
TLOC
| 0.99 | 0.98 | |||
TNOO
| 0.982 | 0.964 |
4.3.4 LUCENE
F1 | F2 | F3 | F4 | F5 | |
---|---|---|---|---|---|
Variabilité (%)
| 88.965 | 6.462 | 2.144 | 1.429 | 1 |
% Cumulated
| 88.965 | 95.427 | 97.571 | 99 | 100 |
LUCENE (Correlation)
|
LUCENE (Square Cosine)
| ||||
F1
|
F1
| ||||
TINVOK
| 0.972 | 0.945 | |||
TDATA
| 0.95 | 0.903 | |||
TASSERT
| 0.86 | 0.936 | |||
TLOC
| 0.967 | 0.739 | |||
TNOO
| 0.962 | 0.925 |
4.3.5 POI
F1 | F2 | F3 | F4 | F5 | |
---|---|---|---|---|---|
Variability (%)
| 47.43 | 36.784 | 8.409 | 5.713 | 1.664 |
% Cumulated
| 47.43 | 84.214 | 92.623 | 98.336 | 100 |
POI (Correlation)
|
POI (Square cosine)
| ||||
F1
|
F2
|
F1
|
F2
| ||
TINVOK
| 0.264 | 0.912 | 0.069 | 0.832 | |
TDATA
| 0.896 | 0.237 | 0.802 | 0.056 | |
TASSERT
| 0.697 | 0.467 | 0.486 | 0.218 | |
TLOC
| 0.887 | 0.399 | 0.787 | 0.159 | |
TNOO
| 0.476 | 0.758 | 0.227 | 0.574 |
4.3.6 IVY
F1 | F2 | F3 | F4 | F5 | |
---|---|---|---|---|---|
Variability (%)
| 48.525 | 40.798 | 6.483 | 3.782 | 0.412 |
% Cumulated
| 48.525 | 89.323 | 95.806 | 99.588 | 100 |
IVY (Correlation)
|
IVY (Square Cosine)
| ||||
F1
|
F2
|
F1
|
F2
| ||
TINVOK
| 0.529 | 0.748 | 0.280 | 0.559 | |
TDATA
| 0.240 | 0.923 | 0.058 | 0.851 | |
TASSERT
| 0.923 | 0.201 | 0.853 | 0.041 | |
TLOC
| 0.780 | 0.613 | 0.609 | 0.375 | |
TNOO
| 0.792 | 0.462 | 0.627 | 0.214 |
4.3.7 Summary
F1 | F2 | Best subset | |
---|---|---|---|
ANT
| TASSERT,TDATA, TLOC | TINVOK, TNOO | TASSERT, TINVOK |
JFC
| TNOO, TINVOK, TLOC | TDATA | TNOO, TDATA |
JODA
| Each metric | TLOC | |
LUCENE
| Each metric | TINVOK | |
POI
| TDATA, TLOC | TINVOK, TNOO | TDATA, TINVOK |
IVY
| TASSERT, TLOC, TNOO | TDATA, TINVOK | TASSERT, TDATA |
All Systems | F1 | F2 | F3 | F4 | F5 |
---|---|---|---|---|---|
Variability (%)
| 58.040 | 33.321 | 4.968 | 2.048 | 1.623 |
% Cumulated
| 58.040 | 91.361 | 96.329 | 98.377 | 100.000 |
Correlation
|
Square-cosine
| ||||
F1
|
F2
|
F1
|
F2
| ||
TLOC
| 0.825 | 0.498 |
TLOC
| 0.680 | 0.248 |
TASSERT
| 0.848 | 0.398 |
TASSERT
| 0.718 | 0.159 |
TDATA
| 0.831 | 0.400 |
TDATA
| 0.691 | 0.160 |
TINVOK
| 0.395 | 0.917 |
TINVOK
| 0.156 | 0.842 |
TNOO
| 0.810 | 0.507 |
TNOO
| 0.656 | 0.257 |
4.4 Investigating the distribution and the variance of the unit test case metrics
4.4.1 K-Means clustering
CBO | LOC | WMC | |
---|---|---|---|
Nb. Obs.
| 1027 | 1027 | 1027 |
Min
| 0 | 2 | 0 |
Max
| 111 | 2644 | 557 |
Mean (μ)
| 12.36 | 182.38 | 35.42 |
St. Dev. (σ)
| 13.45 | 241.36 | 45.82 |
TLOC | TASSERT | TDATA | TINVOK | TNOO | |
---|---|---|---|---|---|
Nb. Obs.
| 1027 | 1027 | 1027 | 1027 | 1027 |
Min
| 6 | 0 | 0 | 0 | 0 |
Max
| 4063 | 1156 | 758 | 516 | 242 |
Mean (μ)
| 147.63 | 36.77 | 21.20 | 35.06 | 10.26 |
St. Dev. (σ)
| 288.87 | 96.36 | 51.08 | 42.44 | 22.19 |
Statistics | CBO | LOC | WMC | TLOC | TASSERT | TDATA | TINVOK | TNOO | |
---|---|---|---|---|---|---|---|---|---|
ANT
|
Nb. Obs.
| 111 | 111 | 111 | 111 | 111 | 111 | 111 | 111 |
Min
| 0 | 5 | 1 | 8 | 0 | 0 | 20 | 1 | |
Max
| 39 | 846 | 178 | 493 | 165 | 47 | 118 | 40 | |
Mean
| 10.49 | 158.64 | 31.31 | 73.16 | 12.03 | 4.56 | 83.72 | 6.43 | |
JFC
|
Nb. Obs.
| 226 | 226 | 226 | 226 | 226 | 226 | 226 | 226 |
Min
| 0 | 7 | 1 | 18 | 1 | 4 | 5 | 2 | |
Max
| 67 | 2041 | 470 | 635 | 143 | 265 | 118 | 45 | |
Mean
| 16.19 | 235.02 | 46.89 | 91.40 | 17.96 | 23.93 | 22.15 | 5.77 | |
JODA
|
Nb. Obs.
| 77 | 77 | 77 | 77 | 77 | 77 | 77 | 77 |
Min
| 0 | 14 | 1 | 27 | 6 | 1 | 3 | 5 | |
Max
| 29 | 1760 | 176 | 2624 | 1156 | 482 | 401 | 242 | |
Mean
| 10.55 | 229.60 | 44.81 | 606.52 | 220.95 | 88.69 | 92.97 | 56.60 | |
LUCENE
|
Nb. Obs.
| 114 | 114 | 114 | 114 | 114 | 114 | 114 | 114 |
Min
| 0 | 8 | 1 | 8 | 0 | 0 | 0 | 0 | |
Max
| 55 | 2644 | 557 | 4063 | 329 | 758 | 516 | 148 | |
Mean
| 9.90 | 193.84 | 35.89 | 192.96 | 30.66 | 31.28 | 32.48 | 9.68 | |
POI
|
Nb. Obs.
| 404 | 404 | 404 | 404 | 404 | 404 | 404 | 404 |
Min
| 0 | 2 | 0 | 6 | 0 | 0 | 0 | 1 | |
Max
| 111 | 1427 | 374 | 2379 | 396 | 188 | 138 | 72 | |
Mean
| 10.39 | 145.42 | 28.42 | 103.00 | 22.36 | 8.44 | 20.94 | 5.42 | |
IVY
|
Nb. Obs.
| 95 | 95 | 95 | 95 | 95 | 95 | 95 | 95 |
Min
| 0 | 5 | 1 | 10 | 0 | 0 | 1 | 1 | |
Max
| 92 | 1039 | 231 | 1019 | 528 | 191 | 92 | 41 | |
Mean
| 18.23 | 189.97 | 34.47 | 131.91 | 29.75 | 21.64 | 25.07 | 9.10 |
Clustering | All systems | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 |
---|---|---|---|---|---|---|
K-means (5)
| 0.910 | 0.867 | 0.923 | 0.968 | 0.886 | 0.839 |
Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | ||
---|---|---|---|---|---|---|
Nb. Obs.
| 587 | 267 | 118 | 38 | 17 | |
CBO
|
Min
| 0 | 0 | 0 | 4 | 3 |
Max
| 44 | 68 | 57 | 92 | 111 | |
Mean (μ)
| 6.06 | 14.461 | 24.56 | 43.03 | 43.71 | |
Std. Dev (σ)
| 5.42 | 10.03 | 12.33 | 19.90 | 28.83 | |
LOC
|
Min
| 2 | 124 | 292 | 592 | 1134 |
Max
| 128 | 288 | 562 | 1039 | 2644 | |
Mean (μ)
| 61.57 | 192.56 | 387.11 | 770.45 | 1458.24 | |
Std. Dev (σ)
| 33.27 | 48.30 | 77.07 | 134.68 | 406.54 | |
WMC
|
Min
| 0 | 3 | 16 | 10 | 10 |
Max
| 86 | 98 | 157 | 231 | 557 | |
Mean (μ)
| 13.33 | 38.69 | 77.86 | 137.34 | 224.29 | |
Std. Dev (σ)
| 8.68 | 13.99 | 22.52 | 48.71 | 154.63 |
Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | ||
---|---|---|---|---|---|---|
Nb. Obs.
| 587 | 267 | 118 | 38 | 17 | |
TLOC
|
Min
| 6 | 8 | 10 | 16 | 18 |
Max
| 1280 | 2035 | 2236 | 2624 | 4063 | |
Mean (μ)
| 84.78 | 146.99 | 289.71 | 399.08 | 779.59 | |
Std. Dev (σ)
| 110.60 | 208.20 | 434.08 | 605.59 | 996.46 | |
Coef. of var (C
v
= σ/μ) | 1.304 | 1.416 | 1.498 | 1.517 | 1.278 | |
TASSERT
|
Min
| 0 | 0 | 0 | 1 | 2 |
Max
| 329 | 1058 | 1014 | 1156 | 396 | |
Mean (μ)
| 17.76 | 36.88 | 84.70 | 130.40 | 149.35 | |
Std. Dev (σ)
| 34.36 | 86.89 | 165.35 | 243.50 | 136.26 | |
Coef. of var (C
v
= σ/μ) | 1.935 | 2.356 | 1.952 | 1.867 | 0.912 | |
TDATA
|
Min
| 0 | 0 | 0 | 0 | 0 |
Max
| 324 | 482 | 393 | 482 | 758 | |
Mean (μ)
| 11.64 | 22.31 | 43.62 | 56.79 | 98.94 | |
Std. Dev (σ)
| 21.62 | 44.61 | 75.64 | 106.23 | 172.48 | |
Coef. of var (C
v
= σ/μ) | 1.857 | 2 | 1.734 | 1.871 | 1.743 | |
TINVOK
|
Min
| 0 | 2 | 1 | 6 | 2 |
Max
| 175 | 192 | 401 | 399 | 516 | |
Mean (μ)
| 26.28 | 34.34 | 60.75 | 72.87 | 86.29 | |
Std. Dev (σ)
| 27.04 | 31.10 | 61.49 | 84.23 | 114.92 | |
Coef. of var (C
v
= σ/μ) | 1.029 | 0.906 | 1.012 | 1.156 | 1.332 | |
TNOO
|
Min
| 0 | 1 | 1 | 1 | 3 |
Max
| 153 | 164 | 242 | 238 | 148 | |
Mean (μ)
| 6.19 | 10.27 | 21.09 | 30.74 | 29.65 | |
Std. Dev (σ)
| 10.38 | 17.74 | 39.20 | 53.56 | 35.95 | |
Coef. of var (C
v
= σ/μ) | 1.678 | 1.728 | 1.859 | 1.743 | 1.213 |
4.4.2 Univariate clustering
Clustering | All systems | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 |
---|---|---|---|---|---|---|
WMC
| 0.910 | 0.869 | 0.941 | 0.957 | 0.889 | 0.672 |
LOC
| 0.877 | 0.943 | 0.912 | 0.895 | 0.768 | |
CBO
| 0.842 | 0.946 | 0.952 | 0.806 | 0.762 |
LOC | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | |
---|---|---|---|---|---|---|
Nb. Obs.
| 707 | 236 | 53 | 26 | 5 | |
TLOC
|
Min
| 6 | 8 | 23 | 16 | 323 |
Max
| 1620 | 2035 | 2624 | 2379 | 4063 | |
Mean (μ)
| 93.92 | 193.04 | 406.76 | 437.58 | 1344.8 | |
Std. Dev (σ))
| 124.39 | 287.19 | 658.85 | 516.76 | 1407.67 | |
Coef. of var (C
v
= σ/μ) | 1.324 | 1.488 | 1.62 | 1.181 | 1.047 | |
TASSERT
|
Min
| 0 | 0 | 1 | 1 | 79 |
Max
| 615 | 1058 | 1156 | 528 | 329 | |
Mean (μ)
| 20.45 | 49.39 | 142.28 | 129.73 | 146.8 | |
Std. Dev (σ)
| 40.98 | 107.48 | 269.95 | 153.84 | 92.81 | |
Coef. of var (C
v
= σ/μ) | 2.004 | 2.176 | 1.897 | 1.186 | 0.632 | |
TDATA
|
Min
| 0 | 0 | 0 | 0 | 9 |
Max
| 482 | 326 | 482 | 323 | 758 | |
Mean (μ)
| 13.11 | 30.42 | 56.93 | 47.65 | 214.8 | |
Std. Dev (σ)
| 27.33 | 53.84 | 108.95 | 68.07 | 275.09 | |
Coef. of var (C
v
= σ/μ) | 2.085 | 1.77 | 1.914 | 1.428 | 1.281 | |
TINVOK
|
Min
| 0 | 2 | 1 | 2 | 17 |
Max
| 175 | 327 | 401 | 138 | 516 | |
Mean (μ)
| 27.08 | 44.64 | 75.60 | 58.85 | 157 | |
Std. Dev (σ)
| 26.94 | 42.80 | 92.46 | 40.06 | 182.80 | |
Coef. of var (C
v
= σ/μ) | 0.995 | 0.959 | 1.223 | 0.681 | 1.164 | |
TNOO
|
Min
| 0 | 1 | 1 | 1 | 3 |
Max
| 164 | 156 | 242 | 94 | 148 | |
Mean (μ)
| 6.86 | 13.19 | 33.40 | 22.69 | 42.6 | |
Std. Dev (σ)
| 11.68 | 23.99 | 60.92 | 23.50 | 53.45 | |
Coef. of var (C
v
= σ/μ) | 1.704 | 1.82 | 1.824 | 1.035 | 1.255 |
WMC | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | |
---|---|---|---|---|---|---|
Nb. Obs.
| 632 | 279 | 93 | 18 | 5 | |
TLOC
|
Min
| 6 | 8 | 20 | 16 | 408 |
Max
| 1358 | 1745 | 2624 | 2280 | 4063 | |
Mean (μ)
| 83.97 | 175.68 | 375.18 | 473.28 | 1224.6 | |
Std. Dev (σ)
| 109.76 | 234.83 | 585.26 | 548.94 | 1422.32 | |
Coef. of var (C
v
= σ/μ) | 1.307 | 1.337 | 1.56 | 1.16 | 1.161 | |
TASSERT
|
Min
| 0 | 0 | 0 | 1 | 104 |
Max
| 528 | 615 | 1156 | 832 | 391 | |
Mean (μ)
| 17.57 | 42.33 | 120.12 | 143.67 | 217.4 | |
Std. Dev (σ)
| 36.70 | 76.55 | 232.38 | 197.31 | 118.50 | |
Coef. of var (C
v
= σ/μ) | 2.089 | 1.808 | 1.935 | 1.373 | 0.545 | |
TDATA
|
Min
| 0 | 0 | 0 | 1 | 19 |
Max
| 161 | 482 | 482 | 323 | 758 | |
Mean (μ)
| 10.90 | 27.34 | 54.66 | 59 | 223.2 | |
Std. Dev (σ)
| 16.16 | 52.08 | 94.16 | 93.15 | 270.37 | |
Coef. of var (C
v
= σ/μ) | 1.483 | 1.905 | 1.723 | 1.579 | 1.211 | |
TINVOK
|
Min
| 0 | 1 | 1 | 6 | 82 |
Max
| 154 | 216 | 401 | 323 | 516 | |
Mean (μ)
| 25.67 | 39.88 | 66.95 | 82.39 | 188.4 | |
Std. Dev (σ)
| 25.55 | 35.83 | 75.98 | 71.34 | 165.06 | |
Coef. of var (C
v
= σ/μ) | 0.995 | 0.898 | 1.135 | 0.866 | 0.876 | |
TNOO
|
Min
| 0 | 1 | 1 | 1 | 11 |
Max
| 82 | 164 | 242 | 188 | 148 | |
Mean (μ)
| 5.76 | 12.92 | 26.55 | 33.5 | 44 | |
Std. Dev (σ)
| 7.64 | 21.94 | 49.65 | 45.04 | 52.21 | |
Coef. of var (C
v
= σ/μ) | 1.328 | 1.698 | 1.87 | 1.345 | 1.187 |
CBO | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | |
---|---|---|---|---|---|---|
Nb. Obs.
| 506 | 284 | 153 | 64 | 20 | |
TLOC
|
Min
| 6 | 9 | 12 | 18 | 16 |
Max
| 1620 | 2379 | 2624 | 1353 | 4063 | |
Mean (μ)
| 91.81 | 175.62 | 236.54 | 149 | 477.85 | |
Std. Dev (σ)
| 144.91 | 298.76 | 421.83 | 206.07 | 854.09 | |
Coef. of var (C
v
= σ/μ) | 1.578 | 1.701 | 1.783 | 1.383 | 1.787 | |
TASSERT
|
Min
| 0 | 0 | 0 | 1 | 1 |
Max
| 615 | 1058 | 1156 | 305 | 391 | |
Mean (μ)
| 20.32 | 46.26 | 65.52 | 38.31 | 93.3 | |
Std. Dev (σ)
| 42.41 | 116.36 | 161.77 | 58.25 | 101.53 | |
Coef. of var (C
v
= σ/μ) | 2.087 | 2.515 | 2.469 | 1.52 | 1.088 | |
TDATA
|
Min
| 0 | 0 | 0 | 0 | 0 |
Max
| 482 | 393 | 482 | 223 | 758 | |
Mean (μ)
| 12.84 | 25.68 | 33.76 | 22.05 | 70.35 | |
Std. Dev (σ)
| 31.17 | 52.80 | 67.72 | 30.42 | 161.49 | |
Coef. of var (C
v
= σ/μ) | 2.427 | 2.056 | 2.006 | 1.38 | 2.295 | |
TINVOK
|
Min
| 0 | 0 | 3 | 1 | 6 |
Max
| 175 | 401 | 399 | 190 | 516 | |
Mean (μ)
| 25.22 | 38.76 | 54.06 | 35.69 | 84.05 | |
Std. Dev (σ)
| 26.18 | 42.52 | 59.67 | 30.24 | 107.34 | |
Coef. of var (C
v
= σ/μ) | 1.038 | 1.097 | 1.104 | 0.847 | 1.277 | |
TNOO
|
Min
| 0 | 1 | 1 | 1 | 1 |
Max
| 164 | 242 | 238 | 54 | 148 | |
Mean (μ)
| 6.76 | 11.05 | 19.46 | 8.66 | 21.85 | |
Std. Dev (σ)
| 13.15 | 22.79 | 37.89 | 10.39 | 33.04 | |
Coef. of var (C
v
= σ/μ) | 1.941 | 2.063 | 1.947 | 1.2 | 1.512 |
4.4.3 Summary
Clustering | All systems | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|---|
LOC
| 0.809 | 1.235 | 0.703 | 0.699 | 0.409 | 0.673 |
CBO
| 1.072 | 1.032 | 0.855 | 0.292 | 0.462 | |
WMC
| 1.097 | 0.755 | 0.730 | 0.493 | 0.684 |
4.5 Exploring the relationships between the internal software class attributes and the unit test case metrics
4.5.1 Correlation between metrics
Metrics | TLOC | TASSERT | TDATA | TINVOK | TNOO | LOC | WMC | CBO |
---|---|---|---|---|---|---|---|---|
TLOC
| 1 | 0.786 | 0.716 | 0.581 | 0.794 | 0.429 | 0.439 | 0.321 |
TASSERT
| 0.786 | 1 | 0.581 | 0.471 | 0.611 | 0.393 | 0.420 | 0.236 |
TDATA
| 0.716 | 0.581 | 1 | 0.417 | 0.561 | 0.339 | 0.366 | 0.305 |
TINVOK
| 0.581 | 0.471 | 0.417 | 1 | 0.588 | 0.355 | 0.369 | 0.342 |
TNOO
| 0.794 | 0.611 | 0.561 | 0.588 | 1 | 0.365 | 0.389 | 0.296 |
LOC
| 0.429 | 0.393 | 0.339 | 0.355 | 0.365 | 1 | 0.936 | 0.710 |
WMC
| 0.439 | 0.420 | 0.366 | 0.369 | 0.389 | 0.936 | 1 | 0.655 |
CBO
| 0.321 | 0.236 | 0.305 | 0.342 | 0.296 | 0.710 | 0.655 | 1 |
Metrics | TLOC | ASSERT | TDATA | TINVOK | TNOO | LOC | WMC | CBO |
---|---|---|---|---|---|---|---|---|
TLOC
| 1 | 0.866 | 0.881 | 0.778 | 0.887 | 0.449 | 0.459 | 0.180 |
TASSERT
| 0.866 | 1 | 0.765 | 0.706 | 0.891 | 0.312 | 0.343 | 0.149 |
TDATA
| 0.881 | 0.765 | 1 | 0.703 | 0.828 | 0.364 | 0.420 | 0.148 |
TINVOK
| 0.778 | 0.706 | 0.703 | 1 | 0.776 | 0.360 | 0.436 | 0.224 |
TNOO
| 0.887 | 0.891 | 0.828 | 0.776 | 1 | 0.284 | 0.326 | 0.127 |
LOC
| 0.449 | 0.312 | 0.364 | 0.360 | 0.284 | 1 | 0.885 | 0.684 |
WMC
| 0.459 | 0.343 | 0.420 | 0.436 | 0.326 | 0.885 | 1 | 0.715 |
CBO
| 0.180 | 0.149 | 0.148 | 0.224 | 0.127 | 0.684 | 0.715 | 1 |
4.5.2 Linear regression analysis
SLR | TLOC | TASSERT | TDATA | TINVOK | TNOO | |
---|---|---|---|---|---|---|
LOC
|
R
2
| 0.201 | 0.096 | 0.132 | 0.129 | 0.080 |
beta
| 0.449 | 0.312 | 0.364 | 0.360 | 0.284 | |
p
value
| <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 | |
WMC
|
R
2
| 0.210 | 0.117 | 0.176 | 0.189 | 0.106 |
beta
| 0.459 | 0.343 | 0.420 | 0.436 | 0.326 | |
p
value
| <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 | |
CBO
|
R
2
| 0.031 | 0.021 | 0.021 | 0.049 | 0.015 |
beta
| 0.180 | 0.149 | 0.148 | 0.224 | 0.127 | |
p
value
| <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
Mean 10 cross-validation | TLOC | TASSERT | TDATA | TINVOK | TNOO | |
---|---|---|---|---|---|---|
LOC
|
R
2
| 0.193 | 0.096 | 0.124 | 0.124 | 0.078 |
beta
| 0.438 | 0.311 | 0.350 | 0.351 | 0.280 | |
WMC
|
R
2
| 0.213 | 0.115 | 0.178 | 0.194 | 0.107 |
beta
| 0.463 | 0.341 | 0.423 | 0.442 | 0.328 | |
CBO
|
R
2
| 0.032 | 0.021 | 0.022 | 0.049 | 0.016 |
beta
| 0.182 | 0.149 | 0.150 | 0.223 | 0.129 |