"In order to answer the research question, how is quality defined in the FLOSS literature, we performed a literature review."
"we searched Google Scholar for journal articles and conference papers containing the terms “open source” and “quality”"
"This process left us with 24 papers, to which we then added 16 from the quality and defect-fixing categories in  that met the above stated criteria.
This left us with 40 papers that defined quality and performed some form of empirical validation of that definition."
"there is little consensus in the FLOSS literature when it comes to defining quality."
defect resolution versus modularity: "Defect resolution rates (amount of defects resolved, speed of resolution) are the best way to measure a community’s commitment to quality, because they recognize that FLOSS is not a static product, but ever evolving. These rates should be calculated per release, and not cumulatively, because the cycle of FLOSS evolution is the release. Researchers should be careful to only include defects and not new feature requests, duplicates, or poorly reported bugs into their calculations.
Modularity is being touted as the main driver of FLOSS quality success, but it needs to be further defined and studied in order to understand how it works."