Nobody. My friend studied econometry. I was appaled to hear that they just take some real process, assume it's governed by some equation then massage all the maths they can out of it.
They consider different equation for the same process (although they usually have favorite one) and never bother themselves with proving if any of them is actually reflected in reality of said process.
It's basically philosophy for people that can do some math.
They also use the math without deep understanding of it (sort of cargo cultishly). That I know because I worked for a prof and a post docs of econonometry on some project later.