>>14455968Rate has been increased to roughly 1/300 to make the games more accessible for people with actual lives. You only need a five chain with the Poke Radar to make shinies begin to appear at a higher rate as well, which is roughly 1/30. There will also be a certain key item rewarded for beating all the leaders in the Battle Maison that lets you freely set the IV's of the next wild or hatched Pokemon, for the same reason.
Source: I'm one of the editors on the strategy guide, this is all information Nintendo sent to us to put into volume two of the guide. 
