zlacker

> Estimates are political tools for non-engineers in the organization. They help managers, VPs, directors, and C-staff decide on which projects get funded and which projects get cancelled.

> Estimates define the work, not the other way around

> The standard way of thinking about estimates is that you start with a proposed piece of software work, and you then go and figure out how long it will take. This is entirely backwards. Instead, teams will often start with the estimate, and then go and figure out what kind of software work they can do to meet it.

So true. But there are times when the thing to be built is known and an estimate is needed [for political reasons, as TFA explains], which is why sometimes it's the other way around.