Has there ever been a major government project that was overestimated in terms of time and budget? If there has, I can’t remember it. It seems to me government projects are always underestimated and I note the HS2 project is now suffering the same fate.

Picture of possible HS2 train.
Credit: Bombardier and Hitachi/PA

They have fallen for the planning fallacy yet again.

Back in my project management days I used to add anything from a third to a half onto time and budget estimates as a matter of course. It’s hard to justify that sort of thing with your bosses when you can only says it’s for the unexpected, but if there’s ever anything you should expect on a project it’s the unexpected.

Most of my projects were IT projects and you could justify some of the additional time and budget on integration. If you’ve got four people working on separate components of a large lump of software, you can guarantee it’ll take a lot longer than you think to get those components talking to one another. And that’s despite the fact that they’re all allegedly observing the same communications protocols.

I think this is a specific example of a more general phenomenon. It is wise to break a project down as much as possible in order to estimate the resources needed but it always takes longer than you think to join the dots at the end.

I guess governments have other pressures on their estimates too. Politics is going to encourage them to underestimate because they want to be seen to be using as little of taxpayers’ money as possible. But I’d argue they’d be better off estimating accurately in the first place — or even overestimating — because they’d get more political mileage by coming in either on or under budget at the end.

What I don’t understand is why the government never learns. I’ve never managed anything anywhere near the scale and complexity of HS2 but, just looking at the way previous government projects have gone, they must surely have known of their propensity to underestimate. If I’d asked the various section leaders for estimates and it totalled up to £56 billion and 15 years, I’d be working on a real estimate of £100 billion and 25 years.

If a complete numpty like me can see HS2 was always going to be underestimated, why can’t the government?