I need a new backup drive.
I don't need 40TB drive, but the site I buy from listed one available.
Thought I might as well click on it and see the price.
The price seemed reasonable for that much storage, But what caught my attention is that the drive ships in 205 days.
Seriously, what are they thinking?
How can they possibly know the drive will ship in 205 days, not 204, 206? The website fell into what I call the precision trap,
which is applying a false level of precision to some estimate or plan.
We often fall into the precision trap because of the math involved in planning.
Let me clarify this with an example.
Suppose a team has estimated that it needs to deliver 100 story points of work to achieve some objective.
They've already calculated their velocity to be 15. Someone on the team does the simple math of 100 divided by 15 to get 6.66. Team members then proclaim
that they will be done in six and two-thirds sprints.
Or hopefully somebody decides to round that up and say it will take seven sprits.
But math like this leads to the precision trap.
You can see from this how the website decided the drive would ship in 205 days.
The precision track persists because we seem wired to like precision.
It feels good to say we'll be in 6.66 sprint.
We must be really smart to know that.
But we should instead favor being accurate over being precise.
Accuracy is about being right.
The easiest way to be right is to less precise For example, that website could have told me the drive would ship in about 7 or 8 months.
That would have been enough precision for me to decide whether to buy it.
When math tells a team they can deliver in six and two-thirds sprints, that's very precise, but it's probably not very accurate.
Just like the ship date of the hard drive, the estimate should be conveyed as a range.
Instead of six-and-two-third sprint, maybe it is six to nine sprinters or even seven to ten sprinter.
When estimating or preparing to communicate a plan, avoid falling into the precision trap.