Size Factors Descriptive Statistics

Ruby Sample

Python Sample

Likelihood of conflict occurrence increases when contributions to be merged have more developers, commits, changed files, and changed lines

See Collinearity diagnostic results here

Ruby Sample (Models II-IV) - Odds Ratios from Regression Assessing Merge Conflicts Factors

Factor Metric	Model I	Model II	Model III	Model IV	Model V	Model VI	Model VII
Changes to a common slice	6.13 ***	4.28 ***	3.80 ***	5.18 ***	4.28 ***	3.78 ***	5.11 ***
Number of commits		3.55 ***			3.53 ***
Number of developers			1.17 ***	1.56 ***		1.15 ***	1.51 ***
Number of changed files			3.27 ***			3.24 ***
Number of changed lines				0.99			0.99
Duration						1.04 ***	1.09 ***
Conclusion delay					1.01	1.01	1.01
Deviance Explained	10.9%	17.5%	19.0%	14.3%	17.5%	19.0%	14.5%

^*** p < 0.001 ^** p < 0.01 ^* p < 0.05

See Collinearity diagnostic results here

Python Sample (Models II-IV) - Odds Ratios from Regression Assessing Merge Conflicts Factors

Factor Metric	Model I	Model II	Model III	Model IV	Model V	Model VI	Model VII
Changes to a common slice	4.39 ***	2.82 ***	3.13 ***	3.60 ***	2.83 ***	3.11 ***	3.52 ***
Number of commits		2.16 ***			2.17 ***
Number of developers			1.36 ***	1.45 ***		1.36 ***	1.44 ***
Number of changed files			2.40 ***			2.17 ***
Number of changed lines				1.64 ***			1.49 ***
Duration						1.18 ***	1.23 ***
Conclusion delay					0.98	0.87 ***	0.85 ***
Deviance Explained	7.1%	14.4%	13.5%	11.6%	14.4%	14.3%	12.7%

^*** p < 0.001 ^** p < 0.01 ^* p < 0.05

Contribution size does not predict the extent of merge damage

Ruby Sample - Size metrics do not correlate strongly with Number of Merge Conflicts

Size Metrics	cor	p-value
Number of developers	0.1841854	< 2.2e-16
Number of commits	0.3234939	< 2.2e-16
Number of changed files	0.3660037	< 2.2e-16
Number of changed lines	0.3607888	< 2.2e-16

Python Sample - Size metrics do not correlate strongly with Number of Merge Conflicts

Size Metrics	cor	p-value
Number of developers	0.1379625	< 2.2e-16
Number of commits	0.3034841	< 2.2e-16
Number of changed files	0.325837	< 2.2e-16
Number of changed lines	0.3024995	< 2.2e-16

Ruby Sample - Size metrics do not correlate strongly with Number of Files with Merge Conflicts

Size Metrics	cor	p-value
Number of developers	0.1846815	< 2.2e-16
Number of commits	0.3238114	< 2.2e-16
Number of changed files	0.3667021	< 2.2e-16
Number of changed lines	0.3604608	< 2.2e-16

Python Sample - Size metrics do not correlate strongly with Number of Files with Merge Conflicts

Size Metrics	cor	p-value
Number of developers	0.1401576	< 2.2e-16
Number of commits	0.3038332	< 2.2e-16
Number of changed files	0.3269765	< 2.2e-16
Number of changed lines	0.3029361	< 2.2e-16