Plan U: Universal access to scientific and medical research via funder preprint mandates

Preprint servers such as arXiv and bioRxiv represent a highly successful and relatively low cost mechanism for providing free access to research findings. By decoupling the dissemination of manuscripts from the much slower process of evaluation and certification by journals, preprints also significantly accelerate the pace of research itself by allowing other researchers to begin building on new results immediately. If all funding agencies were to mandate posting of preprints by grantees—an approach we term Plan U (for “universal”)—free access to the world’s scientific output for everyone would be achieved with minimal effort. Moreover, the existence of all articles as preprints would create a fertile environment for experimentation with new peer review and research evaluation initiatives, which would benefit from a reduced barrier to entry because hosting and archiving costs were already covered.Preprint servers are a low-cost mechanism for providing free access to research findings, and can also significantly accelerate research itself by making results available immediately. This Perspective article proposes that funding agencies should mandate preprint posting to ensure universal free access to the world’s scientific output, as well as stimulate new peer review and research evaluation initiatives.