I heard Scott Adams, the writer of Dilbert, on the radio yesterday. Now, he isn't a political scholar and I am not using him as an expert, but he had a fascinating discussion about Trump and Trump's use of "persuasive speech patterns". He gave specific examples of how Trump's phraseology, even when it turns off many, is designed to create positive effects.
I bring this up because one example he used was the 3% growth number, and he specifically compare/contrasted the effect of Obama downplaying the growth numbers vs Trump setting 3% as the low bar, and what that does to the expectations of the market.
Like I said, he's not an expert but he does have a book out that may be interesting to read - his radio interview really was.
And most here will like his book title:
Win Bigly: Persuasion in a World Where Facts Don't Matter