Finding the right task size in kanban

The Great Pyramids
Image © S J Pinkney
Imagine you were put in charge of building a pyramid for your customer, an Egyptian Pharaoh. You are in a hurry because you have heard bad things could happen if the Pharaoh dies when his gateway to heaven is still a construction site.

It would be nice to have a single large task that says "Build a pyramid", order it from outer space, and have the entire thing airdropped. Unfortunately, you do not have access to alien technology. You have to build the pyramid one stone at a time. In fact, "Put stones on top of each other" is still a very large task. If you do that, you are almost guaranteed to hit trouble down the road. Let's break our task down into smaller chunks first. Later we will see what might happen if you do not do that.

The Great Pyramids
Smaller tasks offer several advantages.

"Build a pyramid" decomposed

Begin by breaking down your task into several rough subtasks. You will get something similar to the list below:

  • Choose the size of the stone blocks
  • Find nearby quarries to supply the stones
  • Build barges strong enough to carry the stones
  • Find a way to load the stones to barges
  • Find a way to lift stones to the top of the pyramid
  • Find enough slave voluntary labor to put the stones in place
  • Supply enough food to keep your labor force working

These tasks are still large, but they give you a much better idea of what you are up against. You should continue breaking each subtask down into more subtasks, but before that, let's take a look at what might happen if you do not do decomposition.

"Build a pyramid" as one large task

Large tasks are actually projects in disguise. With size comes several disadvantages:

What is the right task size for your team?

In kanban, there are additional advantages of using small tasks:

Make tasks as small as possible, but not smaller. Sometimes you can go overboard and make a task too small, but you can always increase its size later. The opposite, however, is not always possible.

Related Article: How kanban can help you increase your team's capacity

© 2010-11 Aycan Gulez