How Come Your Projects Are Always Late?

Mrs Lawther wants an extension to the kitchen, she also wants us to break into the loft and build (or, as she says, create) another bedroom.  Her friend is an architect, she tells us that all the natural light will be uplifting.  My heart on the other hand, is sinking.

Think of the noise and the dust.

No scratch that, think of the cost.  I will need to get a second mortgage the size of a Baltic state’s national debt.

But apparently not, we had the builders round today and chatted it through, we have convinced ourselves that we can do it in three weeks, a month at the outside.  How much can a month’s worth of building possibly cost?

The planning fallacy

I think I have just stumbled across the planning fallacy.  For those of you who haven’t heard of it, the planning fallacy is the fact that despite our best laid plans we always grossly under-estimate how long a project will take.

The planning fallacy is closely related to Murphy’s law but with one striking difference.  Murphy’s law doesn’t exist; dropped toast doesn’t always land buttered side down.  The planning fallacy on the other hand is a demonstrable fact; we do always grossly under-estimate how long a project will take.  Nobody entirely knows why, but psychologists think we only focus on how long it will take to do all the things that will need to go right and completely forget all the things that could go wrong.  They even have a name for it, focal biasWe miss what we aren’t focusing on and so we always under-estimate.

Bosses make it worse

It transpires that people who are in positions of power are more likely to fall foul of the planning fallacy then those who aren’t.  Powerful people expect to get what they want when they want it, they demand it and fool themselves they have total control over the outcome.

The boys will be home by Christmas ~ General Douglas MacArthur (the war in Korea lasted 3 more years)

Team mates make it worse still

People working in teams are also victims of the planning fallacy.  Maybe they don’t want to be neigh-sayers, maybe they want to appear to be efficient, maybe they neglect how much co-ordination is required by big teams, but people in teams suffer acutely, they under-estimate time by the calendar full.

The worst possible scenario:

A “bet your business” sized project and a chief executive pulling together a large task force to deliver that critical strategic initiative.  A heady cocktail of power, desire to please and team work.

You can bet your bottom dollar (if not your business) that they will under-estimate how long it will take, and how much it will cost.


The solution?

The solution isn’t perfect, but it is extremely simple.  When you are planning your project, ask the assembled team for three pieces of wisdom.  Ask them to think of three things that could go wrong, that could turn your project belly up.

Do that, and all of a sudden the time estimates will shoot out.  And they might even be right.

So what could possibly go wrong with my extension?

Nah… not in the UK, I’m sure we can pull it off in 3 weeks

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 Scafolding and Rain

Read another opinion

Image by Thristian


  1. Hi James,
    I listened to short talk by an experienced entrepreneur the other week and when it came to planning his advice was: Expect to make half as much as you plan and that it will take twice as long and cost twice as much to achieve it.

    Sage advice, I believe.

    Want to reconsider your planning assumptions?


  2. I was lucky enough to be recommended a brilliant builder. Our extension and kitchen came in exactly on budget and time. Ben, our builder, produced detailed and sensible Gantt charts, detailed materials schedules and weekly updates. Only over a beer did he admit to using the technique Adrian describes above. Having carefully worked out every detail and cost, then doubled the time required. He realised a long time ago that he was repeatably optimistic and factored this in. It seems to work!

  3. James Lawther says:

    You are of course both right Gentlemen, though I suspect neither the builder, nor the entrepreneur would be welcome around the executive table.


  4. Hello James
    I find that the planning fallacy is particularly acute when it comes to the workplace. Why? Because the context is such that the everyone agrees that it is not Ok to tell the boss the truth.

    I have also noticed in professionals service including consulting. Again the context is such that the guys selling the work do not want to say how long it is going to really take. So there is pressure all round to come up with best case scenarios.

    Of course it is worst of all on large projects where there are lots of interdpendencies. If you dig underneath the surface you are likely to find that the assumption is that EVERYTHING will go just right. Just building a 5% error in each task can double-triple-quadruple the time and cost.


    • James Lawther says:

      I find it amazing that it is not OK to tell the boss the truth, though I suspect you are right. It begs the question though who is the fool? The employee or the boss?


  5. Matt Spielman says:

    I do agree with your observations, and I have witnessed this phenomenon manufacture many crises in projects over my career. But, I would propose that this may not always be a matter of blindness or human failing, but actually used to inject some tension to drive people to be innovative. The President of a division of my company likes to use a quote from Leonard Bernstein: “To achieve great things, two things are needed; a plan, and not quite enough time.”

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