If there’s a sure sign that pro-EU campaigners haven’t learned any lessons from their failed referendum campaign, it’s their lasting dedication to repeating the same flawed strategy. The excitement is palpable in some quarters that a doom-laden civil service forecast about Brexit has been leaked. Already the usual suspects are waving it around as if it’s a great slam-dunk that will change everyone’s minds about the EU.

The problem is, we’ve been here before. The Remain campaign in the referendum had a doom-laden civil service forecast about Brexit to wave around, too. And it had no impact – indeed, for some voters it was an active deterrent, serving as evidence of the desperation of Project Fear.

The flaws in such tactics ought to be obvious. Indeed, there are layers upon layers of problems with them. Anyone’s attempt at a 15-year economic forecast is essentially a guess. Whitehall in particular is reliably and routinely wrong in its economic forecasting. That even applies over the short-term, never mind such long periods of time – the biannual Budget and fiscal statement forecasts are often out after just a few months.

Furthermore, they’re specifically bad at Brexit forecasting; remember that the supposed immediate impact of a Leave vote, not even leaving the EU, was meant to be a full-blown recession, and hundreds of thousands of lost jobs. That was predicted to have already happened by now, but in reality growth has continued and the economy has put on many thousands more jobs. That isn’t vague inaccuracy, or a difference in degree, it is complete error – what happened was the direct opposite of what they predicted, even in the short term.

On top of all that, there’s often presentational jiggery-pokery going on with what the numbers actually say. Remember George Osborne’s prediction that “house prices could fall by 18 per cent” by 2018 if we voted Leave? That turned out to actually be a forecast that house prices would still rise, but not by as much as they would if Britain voted Remain. A lower rise is not the same as a fall, though it was deceitfully spun as such. The same thing is going on here – the leaked report makes forecasts of lower levels of growth, which are misrepresented by some as becoming worse off.

You might find the forecasts appealing, depending on your political view, but what matters is that voters know all of the above – some of it by gut instinct, some of it by habitual suspicion of politicised statistics, and some of it by bitter experience. They know that you can’t rely on such predictions; if you could, both government and private citizens would run their affairs very differently, recessions would never catch anyone by surprise, and there’d be no winners or losers in the markets.

Voters also have a healthy degree of suspicion about the motivations of people who choose to release such forecasts at particular times, be it Osborne doing so just before the referendum or the unknown leaker (rumoured to be in the Treasury) in this instance. People are not stupid, they are alive to the fact that games are played, and that their support is the jackpot being sought. Each time yet another such forecast turns out to be bogus, the power of such stories in future is weakened. The Evening Standard editor is crowing about the leak on Twitter, but he of all people should know better than to imagine this is a game-changer.

Such a story makes great headlines, and attracts lots of clicks, so fair play to Buzzfeed for obtaining what many other outlets would have killed for. But for the above reasons, it doesn’t change minds to anything like the degree that some might imagine – or wish.