From: Eric Hellman <[log in to unmask]> Date: Mon, 22 Jun 2015 09:40:25 -0400 I think you mean "evidence that links journal usage patterns to library purchasing patterns is pretty much unavailable." Because such evidence would take the form of detailed sales histories across a significant numbers of journals. I find it hard to imagine that the more competant commercial publishers would not keep and study their sales data. I'd love to see some of this data opened up, but I'm not holding my breath. Eric Hellman President, Gluejar.Inc. Founder, Unglue.it https://unglue.it/ http://go-to-hellman.blogspot.com/ On Jun 21, 2015, at 7:54 PM, LIBLICENSE <[log in to unmask]> wrote: From: David Prosser <[log in to unmask]> Date: Fri, 19 Jun 2015 06:13:03 +0000 I feel contractually obliged (and I know I’m boring everybody) to point out that the evidence that links journal usage patterns to library purchasing patterns is pretty much non-existent. Setting embargoes based on usage patterns is faith-based, not evidence-based. David