My understanding is that the U of S study is quite exhaustive. I think they're talking about a two-year period to actually complete the whole process. If I were picking a time, I would say two years is what they're working on. They might have things to talk about before. A person would have to ask them directly, but the point of their study is to make sure they do absolutely everything they need to do and not rush it to get an answer.
On April 4th, 2017. See this statement in context.