Overcoming Bias: Planning Fallacy

Via The Guardian, via Chairman Gruber, comes this post from the new-to-me blog, Overcoming Bias. It discusses the research behind a common cognitive bias known as The Planning Fallacy, which is a repeatable, documented error in thinking that apparently explains why we all tend to "underestimate task-completion times."

It's summed up nicely by Gödel, Escher, Bach author Douglas Hofstadter's Law regarding the time it takes to do anything:

It always takes longer than you expect, even when you take Hofstadter's Law into account.

Sounds familiar. From the Overcoming Bias post:

People tend to generate their predictions by thinking about the particular, unique features of the task at hand, and constructing a scenario for how they intend to complete the task - which is just what we usually think of as planning.

[...]

But experiment has shown that the more detailed subjects' visualization, the more optimistic (and less accurate) they become.

Cf: The Optimism Bias.

In my days as a project manager (and in another life as a freelance designer), I got into a habit that has served me well to this day: get the best estimate of both job requirements and time-to-completion that you can find. Then add 20%. Then, when nobody is looking, add another 20%. Then pray.

Although it's no inoculation against the (apparently immutable nature of) Hofstadter's Law -- and you'll still end up short most of the time -- it can help you do one thing much better: manage expectations. Because you're a project manager, not a magician. Magicians get cooler hats.

I think planning a project is ultimately a little like throwing a donut at the moon. You can never actually hit the target, plus you'll be lucky if you aren't hit in the face on the way down.