Via Chris Richardson at Deloitte:
Understanding the official forecasts (and how they pull a rabbit out of their hat)
The official forecasts in the 2017-18 Budget released in May aren’t at all well understood. They say that 3% of national income ($50 billion a year) will go from families and businessesinto Canberra’s coffers over the next four years, with that shift consisting of a big lift in the tax take and a modest nip and tuck in government spending (see Chart i).