  This study investigates the determinants for the uptake of institutional and
subject repository Open Access (OA) in the university landscape of Germany and
considers three factors: the disciplinary profile of universities, their OA
infrastructures and services and large transformative agreements. The uptake of
OA as well as the determinants are measured by combining several data sources
(incl. Web of Science, Unpaywall, an authority file of standardised German
affiliation information, the ISSN-Gold-OA 4.0 list, and lists of publications
covered by transformative agreements). For universities OA infrastructures and
services, a structured data collection was created by harvesting different
sources of information and by manual online search. To determine the
explanatory power of the different factors, a series of regression analyses was
performed for different periods and for both institutional as well as subject
repository OA. As a result of the regression analyses, the most determining
factor for the explanation of differences in the uptake of both repository
OA-types turned out to be the disciplinary profile, whereas all variables that
capture local infrastructural support and services for OA turned out to be
non-significant. The outcome of the regression analyses is contextualised by an
interview study conducted with 20 OA officers of German universities. The
contextualisation provides hints that the original function of institutional
repositories, offering a channel for secondary publishing is vanishing, while a
new function of aggregation of metadata and full texts is becoming of
increasing importance.
