Berdou [in her PhD thesis] conducted interviews with members of the GNOME and KDE projects. She found that paid developers are often identified with the core developer group which is responsible for key infrastructure and often make a large number of commits. Furthermore, she suggested that the groups may have different priorities: “whereas [paid] developers focus on technical excellence, peripheral contributors are more interested in access and practical use”.
Based on these interviews, she formulated the following hypotheses which she subsequently analyzed in more detail:
- Paid developers are more likely to contribute to critical parts of the code base.
- Paid developers are more likely to maintain critical parts of the code base.
- Volunteer contributors are more likely to participate in aspects of the project that are geared towards the end-user.
- Programmers and peripheral contributors are not likely to participate equally in major community events.
Berdou found all hypotheses to be true for GNOME but only hypothesis two and four were confirmed for KDE.