The government's projections are systematically wrong in a specific direction and it is because of the bullshit assumptions used. If you put systematically absurd assumptions in a specific direction into your model, then the output will be systematically absurd too. The assumptions used have been ridiculed not simply by Brexiteers but also by serious economists who oppose Brexit like Paul Krugman. The assumptions include:
- There's no economic gain at all from controlling our own policy vs the EU doing it
- There's no gain from future policy change
- GDP gains from new trade deals with non-EU countries are only 10% of the GDP gains the EU estimates from the same deals
As I said. Garbage In, Garbage Out. The idea there's absolutely no possible economic gains from us either controlling or changing our own policies is utter codswallop, why do we even bother having politicians if that's the case? But to claim that new trade deals are worth only 10% of what the EU estimates they're worth? You'd have to be a total sucker to think that's appropriate. So no doubt you do.