Or even just weight any open access journal more than any closed journal.
That way you can still use historical publications to evaluate researchers on day one, and the evaluations will be accurate assuming most researchers historically each published the same percentage of articles in open access journals, but nobody will want to publish in anything but an open access journal going forward.
That way you can still use historical publications to evaluate researchers on day one, and the evaluations will be accurate assuming most researchers historically each published the same percentage of articles in open access journals, but nobody will want to publish in anything but an open access journal going forward.