  Recent years have seen fast growth in the number of policies mandating Open
Access (OA) to research outputs. We conduct a large-scale analysis of over 800
thousand papers from repositories around the world published over a period of 5
years to investigate: a) if the time lag between the date of publication and
date of deposit in a repository can be effectively tracked across thousands of
repositories globally, and b) if introducing deposit deadlines is associated
with a reduction of time from acceptance to public availability of research
outputs. We show that after the introduction of the UK REF 2021 OA policy, this
time lag has decreased significantly in the UK and that the policy introduction
might have accelerated the UK's move towards immediate OA compared to other
countries. This supports the argument for the inclusion of a time-limited
deposit requirement in OA policies.
