There are a number of reasons for the growth of institutional repositories at academic institutions. IRs provide:
a means to collect and preserve the diverse research outputs of the institution, outputs that might otherwise be scattered and difficult to trace.
a means to showcase the scholarship of the institution, increasing the research profile of the institution and its members.
timely access to research materials to the benefit of individuals and the research community.
In addition, articles deposited in institutional repositories or published in open access journals have been demonstrated to have an advantage when it comes to impact and article citedness. Simply put, articles are cited more frequently when they are freely available and accessible to anyone, via the Internet.