Humans are bad at saying how many hours something will take. But we’re pretty good at comparing two different somethings and deciding which is bigger. That’s why story points and t-shirt sizes are a thing. They let us estimate relatively.

I don’t know how many grams a cherry weighs, and I don’t know how much grams a potato weighs. But I’m pretty sure that a potato weighs at least 10x what a cherry weighs. So if a cherry is 1 story point, a potato is probably about 10. (Or if we’re doing fibonacci sequence story pointing, then a potato is 13.)

And maybe based on the last 6 iterations, we know that we’ve been completing around 30 points per iteration. That’s our average velocity. So based on that, we know we can probably bring two potatoes and a few cherries into the next iteration.

See what we did? We measured velocity and forecasted capacity *using only relative estimates*. So why would we bother trying to guess the weight of a cherry or a potato?

Therefore: why would we bother trying to guess the number of days an engineering task will take?

I also know that a cherry tastes better (to me anyway). So maybe we just bring in 30 cherries and declare potato bankruptcy.

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