The Why #30: Why is my to do list never to done?

4 min readOct 14, 2021


By Dan Monheit, 15.10.21

Question submitted by Sabrina, Ararat

  • Make to do list ✔️
  • Drink morning coffee ✔️
  • Make zoom background ‘presentable’ ✔️
  • Stop adding meaningless tasks to my to do list

Is there anything more two faced than the humble to do list? Part ‘reminder of all we’ve achieved’, part ‘reminder of how little we’ve done’, there’s a unique blend of anxiety that only ‘to do list makers’ can fully understand.

‘Call mum’ has been on there for a week. ‘Do taxes’ for at least a month. ‘Reorganise desktop files’? I think that’s from when I had my old computer.

“How did it come to this?” I hear you cry. What started out as a way to stay focused and on track is now just a reminder of how pathetic I really am. I mean you really are. I mean, whatever.

Well, Sabrina, I’ve got good news for you. Let’s tick ‘read The Why edition #30’ off that list of yours and find out why you, and me, and literally everyone else in the world is never, ever, EVER getting everything ‘to do’, done.

The Planning Fallacy

The Planning Fallacy describes our tendency to hold a confident belief that our own projects will proceed as planned, even with the knowledge that the vast majority of projects do not.

In 1994, Buehler, Griffin and Ross asked psychology students in their final semester for a best case (where everything goes perfectly right) and a worst case (where everything goes catastrophically wrong) estimation of how long it would take them to complete their thesis. On average, the best-case scenario was estimated at 34 days and the worst-case at 48.

How cute!

When life shifted from ‘bright-eyed-planning’ land to ‘oh-crap-now-I’m-actually-writing-a-thesis’ land, the average time of completion turned out to be a whopping 55 days; 60% longer than their best case estimate and a full 15% longer than even their worst imaginable scenario. To make matters worse, the 55 day average didn’t account for a number of students who hadn’t even finished by the time the data collection for the research was finalised!

Turns out we can be a little too optimistic when it comes to planning out random things like thesis writing, which is understandable. Surely it’s a different story for large scale, high stakes projects with lots of experts involved, right? You’d have to ask your friendly IT Director, or perhaps Jørn Utzon, architect of the Sydney Opera House. When a scaled back version of Sydney’s most iconic building finally opened its doors in 1973, it was more than 10 years behind schedule and more than 15 times over budget.

From great feats of engineering to our daily ‘to dos’, there’s a lesson in here for all of us; If it can be planned, it will be underestimated.

Commercially, the Planning Fallacy works in your favour when you have an offering that lets people self project how often they’ll use it. Chances are most people’s assessment of how often they’ll hit the gym, visit the wave pool or require VIP shipping will be way higher than reality.

Behaviourally Yours,

Dan Monheit

PS If you missed the last edition, you can still check out why people speed here.

Bad Decisions Podcast
Learn more about the Planning Fallacy on episode 14 of the Bad Decisions podcast.

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