Relative Story Sizing

Ever wondered how to help keep the “relative” in Relative Sizing? Do you struggle as a team to get consistency with your story points? Well, fear not, there is a way to keep previous stories and sizes in your mind, while in refinement, without trawling through your story tracker. Introducing the Story Point Ruler! Taken from Jimmy Janlen’s book, Toolbox for the Agile Coach – 96 Visualisation Examples, The story point ruler allows the team to see their story point sizing for a number of previous stories. Attached is a handy dandy PDF for you to print out and use (A3 is best).

But how do we use it..?
Good news – it’s simple!

1. Take your printed Story Point ruler and write down a few example stories from your completed work, or sized backlog, next to their size. Each size has 5 spaces (the yellow boxes) for examples.

2. Take your completed Story Point ruler along to refinement

3. When getting ready to size a new story, take a look at your ruler. Which example story on your ruler most closely matches this new story? Consider complexity, unknowns, effort (testing and development), dependencies, risk, etc.

4. Once you have identified a comparable example, use it’s size as the size for the new story.

Anything else we should know..?

Why, yes! Not only does the story point ruler give story size examples, it also has a traffic light indicator to show the size of stories you are aiming for (based on a team with a velocity of around 20 points. We all know each team is different and 1 point for one team does not mean 1 point for another, so you may have to adapt this if your team has wildly different velocity)…

  • Stories in the “green zone” are usually small enough to be taken into a sprint. They have very little ambiguity which, coupled with their size, means that teams would most likely be able to complete more than one of these stories in a sprint.
  • Stories in the “amber zone” are usually small enough to be taken into a sprint, however, they are usually more complex and require more effort so the team runs the risk of not completing their sprint if it is entirely made up of these stories. To reduce risk the team should consider breaking these stories down further, or taking a combination of green zone and amber zone stories in to a sprint.
  • Stories in the “red zone” are usually too large to be included in a sprint as they require considerable effort, are very complex, and may have a lot of uncertainty. They are also usually larger than the team’s velocity so, even if everything runs smoothly, the team would not complete them within a sprint. It’s advisable for the team to refine and split these stories further.

Using the traffic light system, your team will help set itself up for success by reducing the amount of risk and uncertainty taken in to their sprint. Which leads me to…

One last thing…

You’ll notice that there are question marks in place of missing numbers on the ruler. The ruler visualises the modified Fibonacci sequence for sizing (1,2,3,5,8,13,20,40,100). Each question mark can be considered a unit of complexity/risk/uncertainty/etc. So, as the stories get bigger so do the amounts of question marks. I’ve found this useful for helping to explain why we use the modified Fibonacci sequence to size stories instead of giving time estimates. Imagine the unknown growing exponentially.

Let me know if you find this useful in the comments below.

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