From U.S. tax expert Ed Kleinbard, and his forthcoming book We are Better Than This (p159):
“There is no meaning to the growth effects of taxes as such, only to fiscal policy taken as a whole.”
It is another way of explaining that taxes are not a cost to an economy: they are a transfer within it.
Kleinbard is alluding to the myriad ‘independent’ studies out there that seek to attribute all sorts of ‘deadweight’ costs to taxation, without taking into account the other side of the ledger: those often productive things that taxes are spent on. Huge sections of the academic literature on this topic are effectively without merit.