The G7 Open Science Working Group (OSWG) was established to share open science policies, explore supportive incentive structures, and identify good practices for promoting increasing access to the results of publicly funded research, including scientific data and publications [...] To inform the deliberations of the G7 OSWG, three sub-working groups were created to explore key Open Science topics and formulate policy recommendations:●Interoperability and Sustainability of Infrastructures●Research Assessment and Incentives●Research on Research This report pertains to the topic of Research on Research on Open Science. The mandate of the G7 OSWG Research on Research Sub-Working Group consisted of:●Examining questions at the intersection of Research on Research and Open Science, which are relevant to the adoption of Open Science practices.●Helping to mobilize existing Research on Research knowledge to build more evidence-based Open Science policies.●Identifying knowledge gaps in Research on Research that should be filled, drafting a first attempt of Research on Research agenda, to define more efficient Open Science policies.●Proposing actions based on lessons learned, to inform decision-making and accelerate the Open Science journey.The report was informed by two workshops held by the G7 OSWG Research on Research Sub-Working Group, which convened Open Science experts from across the world to discuss topics such as data-sharing, reproducibility, and research evaluation (October 2021), as well as academic, societal, and economic impacts of Open Science (June 2022). It was also informed through Research on Research itself, as well as discussions and knowledge-sharing between all three G7 OSWG Sub-Working Groups (Research on Research, Interoperability and Sustainability of Infrastructures, and Research Assessment and Incentives). The report was also informed by exchanges with individual researchers (see the list of all contributors at the end of the report). It consists of an overview of the Research on Research landscape on Open Science, as well as research recommendations on behalf of the G7 OSWG Research on Research Sub-Working Group. After more than 10 years of Open Science policies, 20 years of Open Science debates and 30 years after the first digital Open Science initiative (ArXiv), there is still much work to be done to achieve a fully Open Science-minded academic landscape. Some studies have demonstrated that close to 50% of contemporary research publications are open access globally ; however, that proportion fluctuates widely depending on fields of research and countries. With regards to Open or FAIR data (findable, accessible, interoperable, and reusable), there are no conclusive studies providing an estimate of the proportion of data globally that is open and/or FAIR. However, the proportion is likely close to 20%, which corresponds more or less to the so-called “big sciences” . In addition, results are still low on issues such as reproducible research and publication bias , and research assessment reform is only in its first stages to facilitate the Open Science transformation. This clearly demonstrates that the path to Open Science has just begun, despite three decades of individual, collective, and political efforts. If the Open Science paradigm is difficult to achieve due to the radical nature of the transformation it implies, the slowness of the associated cultural changes must be understood as resulting from the significant challenge in addressing the cultural changes with adequate, fine-tuned, and contextualized Open Science policies. In other words, if the big picture is clearly drafted, the steps needed to achieve it in a reasonable time are not all clearly identified. Additional efforts to understand obstacles and efficient solutions are needed. In this respect, evidence-based Open Science policies will be of great help, and research on research could play a key role to address the Open Science challenge.