In strict terms to open access - meaning no paywall - green or gold open access. What is the best way to try and measure impact of open versus closed access to articles?
As articles are unique I'm finding it difficult to report potential impact between closed versus open. In just look at the "access" metric I can see that open articles are downloaded and view at a higher rate. However, it's hard to say that it is because it is an open article and not just one that is a higher interest or need.
We do have access to Altmetrics - which is great - it would be good to know if I can use this data to compare to closed research in any meaningful way.