Mandated and Unmandated Open Access: Comparing Green and Gold

Whichever sample and figures one chooses – whether Gargouri et al's 21.9% Green and 1.5% Gold or Björk et al’s 14% Gold and 6.6% Green, the figures fail to bear out Velterop’s prediction that “publishers (the 'gold' road) have actually done more to bring OA about than repositories, even where mandated (the 'green' road).”       Moreover (and this is really the most important point of all), the hunch is the wrongest of all precisely for where OA is mandated, for there the percent Green is over 60%, and headed toward 100%. That is the real power of Green OA mandates.