Using Silent Grouping to Size User Stories
May 22, 2011 25 Comments
User stories are used to describe the functionality delivered in a product or system. Planning Poker is a common technique for sizing user stories, but it can sometimes be challenging. It can be time consuming and teams can get bogged down in unnecessary discussion. There is a technique called Silent Grouping that can be used to compliment Planning Poker, allowing large sets of user stories to be sized in minutes. Silent Grouping has several advantages. It is fast, which in turn leads to significant time and cost savings.
The Silent Grouping Technique
Silent Grouping is a facilitation technique for getting people to group related items without talking. Jean Tabaka has a summary of the technique in her book ‘Collaboration Explained’ as part of a set of techniques used to help teams process large amounts of information. Jean’s variation of the technique is described in the context of conducting a retrospective, but it is equally applicable to grouping user stories.
There are variations in how this technique is applied. I usually apply the technique in four parts: preparation, individual placement, group placement, and, finally, discussion and reflection. Each part serves a specific purpose, as shown in the table:
|Lay the ground rules; set expectations|
Round 1: Individual Placement
|Quickly get an initial size estimate for all of the user stories|
Round 2: Group Placement
|Give everyone an opportunity to (silently) provide input to all user stories|
Discussion and Reflection
|Resolve any disputes; reflect on experience; gain consensus before moving on; discuss insights|
The facilitator prepares the board. The columns represent the groups referred to in the name of the technique. The team needs to decide on a scale to use for user story point sizes. Many agile teams now use the Fibonacci sequence for user story point sizes. The user stories should be placed somewhere visible and easily accessible so a smooth flow can be established. Pinning or sticking them to an adjacent wall space or laying them out on a table works well. The board should look like this before the team begins:
It is a good idea to prepare a Parking Lot for any user stories whose grouping cannot be agreed. I usually put this just beside the Grouping board.
Choose and agree a mid-size user story for starting off. This is the bench mark against which the first few user stories will be compared. After that, triangulation will take over and people will size the current user story against all currently sized user stories.
If the team is new to Silent Grouping, the facilitator explains the technique as part of the preparation, and answers any questions.
Round 1: Individual Placement
Team members take turns, one at a time, to place one user story on the board. The goal in this round is to get all the user stories on the board, and hence get an initial size estimate for all user stories.
I find that simply forming a line is the easiest way to run this part of the exercise. As each person takes their turn, they rejoin the back of the line.
Round 2: Group Placement
The team stands around the board. At this point all user stories are on the board. Team members take turns stepping forward and moving one user story at a time. The goal in this round is to get to team consensus on the size of all the user stories.
There can be contention in this round. A user story can get moved repeatedly, e.g., one team member can move a user story, e.g., from a 5 to an 8, and another team member can move it back to a 5. The team has been instructed to consider why the user story might have been moved. Very often, this act of observation and conscious consideration is enough to resolve the disagreement, and the parties will agree on a size without any verbal discussion.
It can happen that two or more people will move a user story back and forth between two (or more) columns, and nobody is prepared to compromise. This is generally a signal that more discussion is required for this specific user story. As the facilitator, when you observe this interaction just remove the user story form the board and place it in the Parking Lot that you prepared earlier. In practice I have found that this tends to occur relatively rarely.
Risks to watch out for in this round include people not participating. This can take a number of forms. They can stand back and just observe, and not size anything after Round 1. They can become disengaged and not observe the proceedings at all. Both of these can be signs of underlying issues. This is where the skill and experience of the facilitator is important, first in recognizing the symptoms, and then dealing with it.
Discussion and Reflection
The facilitator facilitates a short discussion between the team to gauge the level of confidence in the sizes. The Fist of Five is a good technique to use here. It quickly gives a sense for how confident the team is in the sizing that they just performed.
I used to use a ‘?’ column to group user stories that people felt could not be sized because there were too many unknowns. Planning Poker has a ‘?’ card too. However, I found that this provided too easy a way out. I want to provide a situation where teams are forced to either make a decision or openly disagree with each other and question the size of the user story. Decide what’s appropriate for you, but these days I prefer to not use the ‘?’ column.
Summary of Benefits
I have observed the following benefits from using the Silent Grouping technique:
- It is very fast. You can size large sets of user stories in minutes.
- It is scalable. I have used this technique with up to 8 Scrum Teams (55 people) in parallel, to size 677 user stories in 28 minutes.
- It very quickly surfaces any unknowns or areas of disagreement within the team.
- It is inclusive. Everyone gets the opportunity to comment on all user stories.
- It works well as a compliment to Planning Poker. You can size initial benchmark user stories using Planning Poker. For any user stories that don’t gain consensus during Silent Grouping, you can size those with Planning Poker.
- Because the Silent Grouping technique explicitly disallows talking, it is easier for more introverted team members to exert their influence. Conversely, it is harder for more dominant team members to exert their influence just by force of argument or discussion – something that can happen in Planning Poker.
- If there are language barriers in your team, e.g., if you work with global teams who do not share a common first language ( a very common scenario these days), then Silent Grouping is a good leveler.
- You can sometimes observe a noticeable delay among Planning Poker players as they wait for others to show their hand first. With Silent Grouping, particularly in Round 1, people must make a decision themselves without influence from others.
- Silent Grouping applies the wisdom of the entire team to quickly size large sets of user stories. Just like in James Surowiecki’s book, the team will be familiar with the problem domain already. E.g., in one of the early examples in Surowiecki’s book, the people guessing the weight of the cow were all experienced farmers. If it is a truly new problem domain for the team then they need to spend some time before sizing just getting familiar with the problem domain.
Playing Silent Grouping at the XP2011 Conference
I had prepared some slides for my session at the XP2011 Conference, but as it turned out, I did not use the slides. Instead, I decided to run an actual Silent Grouping session. I asked for seven volunteers to pretend to be a Scrum team, and one other volunteer to be a time keeper.
When teaching this technique it’s useful to have a backlog of user stories already prepared. Rather than try to come up with a contrived product example, I like to use animals. Most people are familiar with most types of animals, so it makes for a good problem domain. To simulate reality, add in a couple of unfamiliar animals, or some that might appear to be ambiguous. For the XP Conference I used 42 sticky notes with stickers of animals. Some animals were represented more than once.
The team sized all 42 user stories in about six minutes.
Several people who came to my session at the XP Conference tried it out when they got back to work, including @ruby_gem.
The slide deck is here:
My talk at XP2011 was based on a research paper that I submitted to the conference, and was published as part of the conference proceedings. I was delighted to be named in the final four at the conference banquet for the award for Best Research Paper.
The paper draws on experiences of seven Scrum teams as examples. The paper shows how to apply the technique with co-located teams, and includes an example of how it was used with distributed teams. The paper is 15 pages long and contains some data, charts and more detail on the technique and its application. The proceedings are available from Springer.
Let me know how you get on
I keep records every time I run this, and I also keep records of other ScrumMasters and coaches that use it. I would love to hear how Silent Grouping works out for you. Get in touch and let me know the following. I’ll be happy to credit you in any future papers.
- Team size
- Number of user stories
- Time to size the user stories
- Number of user stories that needed discussion afterwards
- Number of user stories sized with Planning Poker
- Any comments, experiences or insights from you or your team