Based on the amount of workers active on the project and seeing the cranes moving.Based on what?
There's still superstructure showing the last picture I saw and the outside is usually the EASY part of Disney rides.
Still...I can understand the hope that they are getting a lot closer to finishing and can meet the schedule.
Maybe they are actually paying for overtime and bonuses for the first time in forever? (No pun intended)
There's a real reason to get it done by early 2017 though...studios is gonna be a warzone that may actually make people walk away angry