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FLOSSmole data confirms declining GPL usageMatthew Aslett, June 13, 2011 @ 10:45 am ET
Last week we published a post looking at some statistics suggesting a decline in the usage of the GNU GPL.
The post sparked some interesting debate, not least about the validity of Black Duck Software’s numbers, which we had used to compare usage of the various FLOSS licenses over recent years.
While we have no specific reason to doubt Black Duck’s figures, Bradley M Kuhn, in particular, suggested that Black Duck’s data should be “ignored by serious researchers” since the company doesn’t disclose enough detail about its data collection methods.
He added that “AFAICT, FLOSSmole is the only project attempting to generate this kind of data and analysis thereof in a scientifically verifiable way”.
You can probably guess where this is going…
In order to test Black Duck’s data we downloaded FLOSSmole data from four sources for which both current (May 2011) and historical (October 2008) data was available: Rubyforge, Freshmeat, ObjectWeb and the Free Software Foundation.
We then sorted each data set and generated subtotals for each license type, checking the data manually to make sure we had combined all the relevant data (data tagged GPL2, GPLv2 and GNU GPLv2 for example).
Given the wide variety of ways in which the various GNU Public Licenses have been tagged across the four data sources (a huge number of Freshmeat projects are tagged simply “General Public License” with no version number) it also made sense to group the licenses together into the GPL family (including LGPL and AGPL).
The results show that the GPL family of licenses accounted for 70.77% of all 53,914 projects in the sample in October 2008. In May 2011 that figure had declined to 59.31% of 54,800.
As a reminder, the figures from Black Duck showed the proportion of projects using the GPL family of licenses had declined from 70% in June 2008 to 61% today. So the FLOSSmole figures actually show a more rapid decline in GPL usage than Black Duck’s.
One important point to note is that a significant number of projects (5,775) in the 2011 Freshmeat data do not have license details. Removing these projects from the sample would result in the GPL family of licenses representing 66.3% of 49,025 projects in 2011.
Either way, the FLOSSmole results confirm a decline in GPL usage.
UPDATE: Just to be clear, the figures for ‘GPL family’ above include both LGPL and AGPL as well. FLOSSmole’s figures show both increased from 2008-2011, from 6.22% to 7.21% and 0.11% to 0.36% respectively.
2ND UPDATE: Of course, the % of total projects is only one way to measure adoption, and some people will argue it’s not a particularly good one. Certainly we’re not going to get carried away with the fact that the % of projects hosted by the Free Software Foundation using the GPL family has declined from 81.2% to 76.7%. Although it is kind of interesting.
*Howison, J., Conklin, M., & Crowston, K. (2006). FLOSSmole: A collaborative repository for FLOSS research data and analyses. International Journal of Information Technology and Web Engineering, 1(3), 17–26. (more)
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