The Free Software Foundation has responded to our analysis of figures that indicate that the proportion of open source projects using the GPL is in decline.
Specifically, FSF executive director John Sullivan gave a presentation at FOSDEM which asked “Is copyleft being framed”. You can find his slides here, a write-up about the presentation here, and Slashdot discussion here.
Most of the opposition to the earlier posts on this subject addressed perceived problems with the underlying data, specifically that it comes from Black Duck, which does not publish details of its methodology. John’s response is no exception. “That’s not science,” he asserts, with regards to the lack of clarity.
This is a valid criticism, which is why – prompted by Bradley M Kuhn – I previously went to a lot of effort to analyze data from Rubyforge, Freshmeat, ObjectWeb and the Free Software Foundation collected and published by FLOSSmole, only to find that it confirmed the trend suggested by Black Duck’s figures. I was personally therefore happy to use Black Duck’s figures for our update.
John Sullivan is not overly impressed with the FLOSSmole numbers either, noting that while they are verifiable, they do leave a number of questions related to the breadth and depth of the sample, the relative activity of the projects, whether all lines of code and applications should be treated equally, and how packages with multiple licenses are treated.
These are all also valid questions. As we previously noted, a study that *might* satisfy all questions related to license usage would have to take into account how many lines of code a project has; how often it is downloaded; its popularity in terms of number of users or developers; how often the project is being updated; how many of the developers are employed by a single vendor; and what proportion of the codebase is contributed by developers other than the core committers.
John offers some evidence of his own that suggests that the use of the GPL is in fact growing. Anyone hoping for the all-encompassing study mentioned above is in for some disappointment, however. It is based on a script-based analysis of the Debian GNU’Linux distribution codebase.
Nothing wrong with the script-based analysis – but a single GNU/Linux distribution considered to be a representative sample of all free and open source software?
That’s not science.