Relative estimation (or relative sizing) is my favourite way to find out the overall size of a project during the inception. I like it because it’s a quick and easy way to handle lots of stories, and it handles lots of uncertainty really well.
Relative estimation is not my idea and you can find lots of info on the web. The below are just the instructions I use. I hope you find them useful…
Before you can start estimating, you need to have some stories to estimate!!! The below instructions assume you are drawing to the end of a project inception. By this point, you have written story cards that represent the work you need to do to complete the project (or maybe just one of the milestones/epics).
I find it easiest to use physical index cards, I add them to my electronic board after estimation.
You can use post-its, but shuffling is harder because they stick together!!
Here’s how it works
1. Get a very long table (long enough for all the story cards to be placed in one row — probably several tables end to end)
2. Collect all the story cards for the project from your story workshops and ensure each has the relevant epic marked if they belong to more than one.
3. Shuffle the cards
4. Take the top card and place it in the middle of the table
5. Take the next card, and the team decides whether it should be placed left (less complex) or right (more complex) of the first card
6. Repeat for the next card (cards can go between any they need to in order to have fewer complex cards on the left and more on the right
1. When you’ve placed all the cards in one row you start giving them numbers.
2. Choose the number scale the team prefers (Fibonacci Sequence 1 to 13 is quite common)
3. Starting at the left end (least complex), the first card is the lowest number in your scale. Start walking slowly along the row and decide the point where you change from your first number to the next. Mark that point with a post-it.
4. Keep moving along the line until you get to the next number.
5. Keep going like this until you have groups of complexity all the way along the line.
1. Now write the numbers onto all the cards
2. You now have a complete set of estimated cards for the project. But don’t forget that things will change. During the project you might decide some of the cards are not needed, and maybe you need some others. Also, you might decide that some of the estimates are incorrect (and therefore should be changed). This is all normal.
Estimation is complete. But that’s only part of the story. You now need to follow you progress and turn the estimates into a prediction for delivery. More on that soon…