Not sure if this was aimed at the general public, or myself specifically, but all I did was post a link. Last night I also saw that the FT listed an article advising similar figures (4.4%?). Today the governments own analysis is also saying the same.
Predicting the future exactly is impossible. But you can develop strategies with regard to the most likely outcomes based on the evidence and information available.
Currently, the vast majority of the evidence backs up the position that the majority of people will be worse off, and the country financially will be worse off. All the reports I have seen suggest GDP - the measure you put forward - is going to go down.
We can only make a decision based upon the information available. The referendum itself was pole axed by a distinct lack of information. We're now getting some information, and economically, it does not look optimistic.
I apologise if I have over-reacted to your post, or taken it the wrong way.