[ Thanks to Peter
Judge for this link. ]
“During 2011, the company tested open source projects that
totalled over 37 million lines of code and the report also details
the results of 300 million lines from anonymous proprietary
software produced by Coverity Scan users.“On running the scans, it was found that the average defect
density (number of defects per 1,000 lines) for open source was
0.45. In the proprietary code the same scan produced an index of
0.64. In both cases this is better than the 1.0 average defect
density measured in commercial software.“The cleanest code was found to be Linux 2.6, PHP 5.3, and
PostgreSQL 9.1 which weighed in at 0.62, 0.20 and 0.21
respectively. Coverity said that this recognised superior code
quality defines the projects as industry benchmarks.”