It happened again. Another question on one of the Slack groups I frequent: How do we estimate a project with a Q3 deadline?

If you believe as I do that software development is inherently unpredictable, the answer is simple, though often baffling: You don’t.

To be clear, I’m not saying it’s impossible to come up with some vague idea of how long a project will take. Instead I’m saying that it’s wasted effort to do so.

In this case, the project was going forward. It wasn’t a question of “should we do the project or not?” Rather, the most likely outcome if the project could not be achieved before the deadline would be to cut scope.

Here’s the wonderful thing about incremental software delivery: Scope cutting is just built in!

Here’s how it works. When you look at the outcome you’re aiming to achieve before the deadline:

1. Select the single most important or impactful task that will move you toward that goal, and provide some value immediately.
2. Do that task, and deliver it completely.
3. Go to #1.

If you work in this way, always doing the most important task which delivers some value, then whenever the deadline arrives, whether it’s tomorrow or at the end of Q3, you’ll be guaranteed to have done the most impactful bits. The bits that weren’t done were the scope that was cut. And you didn’t waste any time at all estimating how long each task would take.

The funny thing is: This is exactly how incremental software delivery works without a deadline, as well.

The goal of incremental software delivery is to always be providing the most value possible right now. Which should almost always be the goal, with or without a deadline.