We compared quality and quantity of contributions made
by students to contributions made by editors who joined
Wikipedia at the same time as students but were not part of
the initiative and who edited articles associated withWikiProject
Psychology, Sociology, and Neuroscience on Wikipedia.
We selected these disciplines because they are likely to have
content that is similar to that edited by the students in the initiative.
Editors can explicitly join WikiProjects, but only a
subset of those who edit relevant articles actually do so. To
include a more complete list of editors, we defined an editor
as associated with aWikiProject as long as they edited at least
one article tagged with that WikiProject label. By this definition,
2,066 new editors were associated with WikiProject
Psychology, 2,148 new editors were associated withWikiProject
Sociology, and 276 were associated with Neuroscience.
To compare the quantity of contributions of students versus
non-initiative members associated with these WikiProjects,
we conducted a regression analysis with group membership
as an independent variable and number of words added as the
dependent variable. We used a negative binomial model to account
for skewness of the data. Compared with members of
these WikiProjects, students added significantly more words
to the articles they edited. The mean of number of words
added by each group is presented in Table 4.