How do you estimate user stories?
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It’s like asking “How long is a piece of string?”, or is it? I wanted to see if there was a science behind how we estimate a user story?
You could sit in a workshop or planning meeting for hours before deciding if one story is an ‘X’ number of man-hours. Even after agreeing, you can never really be confident until you get into the details. The complexities of trying to use science to estimate a user story is an activity that comes in time. Still, it seems almost impossible at the beginning when you have a new team. However, that does not mean that you remove the concept of time from your work, that would be anarchy!
One of the simplest and more effective ways to estimate in our work environment, that is highly time-restricted, is through a technique in the Agile industry known as planning poker. This method includes the Fibonacci sequence that represents story-points. I know it sounds like the start of an awful joke but hear me out.
The Method
Planning poker is a technique for estimating, mostly used to determine effort and size of user stories (bite-sized units of work) resulting in quick but reliable estimates.
You play the game using, a deck of unique cards which are composed of the Fibonacci sequence, meaning the cards will have the numbers — 1, 2, 3, 5, 8, 13, 21, 34, etc. These numbers represent “Story Points” (how complicated something is). Each participant has a deck of cards or at the very least should have a pen and paper to write a number down.
The team must select one participant as the mediator who has the job of reading the user story for which the estimation is made. It is useful here to start a small discussion around the story, for instance, asking “Have we done this before?” “Is this story properly refined?”
The mediator must make sure that the discussion does not drag on. At a suitable break in the conversation, each participant should be invited to select a card from their ‘hand’ or write down a number representing their estimate privately.
Once everyone is ready, it’s time for a showdown to see what views participants have, making sure to reveal at the same time. It’s poker after all 😜.
In the first round, the estimations will likely vary. Those who have selected the most extreme estimates should make sure to voice their reasons why. I would recommend the mediator to take notes on the discussion. It will be useful when developing the respective stories. After the conversation, each participant re-estimates by again selecting a card.
As you practise the technique it will become more succinct, for now, repeat the process till the estimates converge to a single story point. In time you will be able to tweak it to suit the team’s needs.
The Benefits
Multiple Opinions
Through this approach, by asking numerous individuals in the team to judge the complexity and effort of a story. Each provides an estimate relying on their experience, intuition or gut feel. Ultimately resulting in discussing various opinions quickly to align the team’s understanding of a user story and move forward.
Comparisons
If you take a macro view of the user stories you are writing, there is likely to be a trend of similar types. Through this technique, you are allocating stories a story point to potentially use as a baseline in the future. Meaning that although the new stories will be complex, you will have an idea of how long they could potentially take through accurate results.
Story-Splitting/ Refinement
The user stories that are discussed should be in the range of two to five days to finish. Therefore if you have a story that has a story point of 13, it is too big and is likely to be complicated. As a result, refinement will need to occur for an executable story. Check out my article on how to write a good user story if you need help here.
Forces You To Choose “More Or Less”
The unique numbers force each participant to think harder about, “is it a 5, an 8, or a 13?”, there is no in-between. The brain can intuitively recognise between the numbers as distinct sizes. For example, with the numbers 1 and 2, there is a difference of 1. At the same time, with 5 and 8 there’s a difference of 3.
Planning poker invites discussions.
It’s the perfect conversation starter. What better way to talk about something when multiple people disagree or agree on a topic. However, everyone must remember that the conversations are meant for furthering the overall understanding of a user story, to aid alignment.
Take nothing personally!