Open Educational Resources (OER) are being used more and more intensively as an efficient tool for sharing knowledge in the educational community at all levels. As a consequence, OER play a fundamental role in the teaching-learning process. Therefore, it is of great importance to take care of the OER quality in order to ensure that they allow the intended educational objectives to be achieved as efficiently as possible. Main definitions on OER and required properties are very well defined by UNESCO. Additionally, UNESCO has also developed regulations, polices, recommendations and guidelines, as well as an OER Dynamic Coalition to promote and support networking and sharing of information to create synergies around the OER use and generation. In its Basic Guide it is asked: “Who guarantees the quality of OER?”

To contribute to this research question is one of the tasks of the “Gate2Math: Open multilingual smart library for mathematical resources supporting efficient learning” project. Gate2Math is an ERASMUS+ innovation project (2022-1-EE01-KA220-HED-000089461, September 1st, 2022- August 31st, 2025), integrated by six European universities, aiming to develop and implement a Smart Library of OERs in the field of mathematics in the context of engineering, in seven different languages. Complete information on objectives, partner universities, intellectual outputs, dissemination activities and contact can be found at https://gate2math.eu.

Within Gate2Math project two rubrics for OER quality assessment have been designed. This paper presents the statistical study in order to validate the equivalence between a comprehensive rubric and a reduced rubric by taking into account the most relevant Key Performance Indicators related with and efficient learning/teaching methodology (Content, Didactics, Technical Characteristics, Accessibility and Inclusive Communication). Main conclusions and discussion on differences, strengths and weaknesses of both rubrics will be introduced and underlined. Final output of this approach allows to propose to the educational community a more efficient OER quality assessment methodology, easy to be used and fully understandable.

Keywords: Open Educational Resources, Key Performance Indicator, OER Assessment Methodology, Digital Library, Higher Education, Gate2Math, ERASMUS+ Project.