Piotr Zakrzewski Thanks for clarifying this, that does indeed explain the 91.67% The 5 merges rule sounds reasonable but without supporting evidence it could skew your results. Once you got your first PR through then you know (and appearantly aligned with ;-)) the "culture" of the project (coding style, doc style etc, way of commenting). The project also gets to know you a bit ("that person from last PR") so you start to build trust. Both items will make it easier to get a second PR merged. On the other hand: newbies with more ambition than skill will get their PR rejected and will never try again. Only the newbies with good enough skills and/or willingness to invest time will get their PR merged. I have submitted to repo's where people asked me to rebase twice because they put their own PR's first. I got my PR merged, but it was not really a hospitable experience. Looking at the cold hard figures I got my PR merged, so it counts towards an increased chance of getting merged. So although the figures are right (even the ones on Julia ;-)) I would not draw any conclusions on hospitality based on this data. If you really want to know what your chances are on a succesful PR then my advice would be to get to know the project and raise an issue stating that you intent to submit a PR to do XYZ. If that issue goes stale or your intent is dismissed then you know enough ;-) Personally I also prefer people to first submit an issue and discuss instead of starting stealth and suddenly submerge with a fully loaded PR that changes 75% of my project ;-) And then some suggestions for other stats that could be useful: last time since merge (helps to find projects that most likely been abandoned) time between creation of issue/PR and first action (comment/triage/merge/close) (if this takes too long the project might be understaffed) total number of issues/PR's over time (is a project still mainstream or moving towards maintainance mode or worse) Kind regards, Hans