Robert_Charlton - 9:32 pm on Feb 25, 2013 (gmt 0)
Matt's video confirms only that the loss of PageRank in a 301 currently is essentially the same as the loss in a link. He doesn't actually confirm the 15% number (which has been my rule of thumb number too).
He also does not in any way suggest, as Andy emphasizes, that a link and a 301 are equivalent in other ways... and probably for reasons of secret sauce recipes, needs to steer clear of why that is.
Matt mentioned that he first brought up the dissipation of PageRank through 301s in order to discourage the use of 301s instead of links... and 1script, you're right, it doesn't make sense to me either, but apparently some SEO Matt had spoken to had once been contemplating doing this.
See this excellent discussion about 301s and PR loss from March 2010, prompted in part by Matt's prior comments on the topic....
301 Redirect Means "Some Loss of PageRank" - says Mr Cutts