Development on the next Mass Effect game is in neither the early stages nor the late stages, prompting BioWare studio director Yanick Roy to describe its development status as being "somewhere in the middle."
Roy said as much in response to a question on Twitter (spotted by IGN) asking him to clarify conflicting reports about the status of the next Mass Effect game. He has been hesitant to reveal much more than that on Twitter. Early last month, he tweeted, "I apologize for not having any new info on the next Mass Effect for you. It's because our focus is on doing it right over doing it fast!" More recently, he was asked whether the game would have a presence at this year's E3, to which he expressed his hesitation "to start announcing announcements."
Little is known about the next Mass Effect game--sometimes referred to as Mass Effect 4, despite no title having been announced--beyond the fact that it leaves the story of Commander Shepard and the first three games behind. BioWare began teasing images from the new game in November (one of which you can see above), and shortly thereafter we learned it is already playable and "fresh but recognizable."
A release window for the next Mass Effect has yet to be announced. While we could very well begin seeing official announcements made at any time, based on Roy's tweet, it doesn't sound as if you should expect any announcements regarding a release in 2014.