Updated: Mar 2, 2022
The “bucket system” is a way to ensure the estimation process for many stories (greater than 40 and less than 500) is done efficiently and effectively. This process uses a sequence similar to planning poker. A group of people (5 - 25 participants) estimate items relative to each other by placing them in “buckets,” representing a relative definition of a work effort.
The bucket system is particularly suitable for use in an Agile environment, as it has all the qualities you would expect to see in an Agile estimation technique:
It saves time as it allows the team to estimate a hundred items in little time.
It is based on relative estimates.
It allows each participant to share their insights and equally contribute to the estimation process.
Let’s review how a typical estimation process is done using this technique:
The meeting facilitator lays a sequence of cards with the labels 0, 1, 2, 3, 4, 5, 8, 13, 20, 30, 50, 100, 200 in a location accessible to all participants. These cards are the “buckets," where each one represents a different work effort.
Pick an item at random from the collection. Please read it to the group and put it in a bucket labeled eight as a reference for all other stories.
Pick another item at random from the collection discuss all its requirements and features with the group. The group determines its relative position on the scale. Once there is an agreement, put it in the appropriate bucket.
Choose another item at random from the collection. Please share it with the group that will now estimate it relative to the first item (The one we put in bucket 8). For example, if it is estimated at more than double the first item, it would be placed in the "20" bucket.
Now that the team is warmed up, it is time to initiate the "divide and conquer" approach. This is where the remaining items in the collection are equally distributed among participants.
Participants then work independently through their items to estimate each item based on their judgment (without the need to discuss it with other participants) and place them in the appropriate buckets. Note: If a participant feels uncomfortable estimating an item or does not understand its meaning, the item can be moved to someone else. The facilitator should ensure it's done based on mutual agreement between the two sides.
Once all items are placed, the participants start to review the items in each bucket. They look for items they know well and ensure they are in a suitable bucket. If they find any mistakes, they can discuss them until they have reached an agreement.
Guidelines and tips for an efficient estimation process
The facilitator should ensure that nobody changes stories from one bucket to another unless other participants approve or review.
There may be situations where most of the items are in one bucket. In this case, take several of them and re-review them with the team. This ensures the team didn’t put them in the bucket for convenience.
This technique will work best when you have many stories to be estimated by many participants.
If participants struggle with their estimation, they should share their remaining items with participants who are already finished and can help promote the estimation flow.
The division of items among participants does not need to be equal.
Stories cannot be placed "between" buckets to represent a more precise estimate.
At the end of this session, all items should be prioritized within each bucket.