Planning poker
Encyclopedia
Planning Poker, also called Scrum poker, is a consensus-based technique for estimating, mostly used to estimate effort or relative size of tasks in software development
. It is a variation of the Wideband Delphi
method. It is most commonly used in agile software development
, in particular the Extreme Programming
methodology
.
The method was first described by James Grenning
in 2002 and later popularized by Mike Cohn
in the book Agile Estimating and Planning.
, describes some software that needs to be developed.
The cards in the deck have numbers on them. A typical deck has cards showing the Fibonacci sequence including a zero: 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89; other decks use similar progressions.
The reason for using the Fibonacci sequence is to reflect the inherent uncertainty in estimating larger items.
One commercially-available deck uses the sequence: 0, ½, 1, 2, 3, 5, 8, 13, 20, 40, 100, and optionally a ? (unsure) and a coffee cup (I need a break). Some organizations use standard playing cards of Ace, 2, 3, 5, 8 and King. Where King means: "this item is too big or too complicated to estimate." "Throwing a King" ends discussion of the item for the current sprint.
Optionally, an egg timer
can be used to limit time spent in discussion of each item.
The meeting proceeds as follows:
The cards are numbered as they are to account for the fact that the longer an estimate is, the more uncertainty it contains. Thus, if a developer wants to play a 6 he is forced to reconsider and either work through that some of the perceived uncertainty does not exist and play a 5, or accept a conservative estimate accounting for the uncertainty and play an 8.
A study by K. Molokken-Ostvold and N.C. Haugen found that estimates obtained through the Planning Poker process were less optimistic and more accurate than estimates obtained through mechanical combination of individual estimates for the same tasks.
The estimate becomes anchored when the product owner says something like, "I think this is an easy job, I can't see it taking longer than a couple of weeks", or when the developer says something like, "I think we need to be very careful, clearing up the issues we've had in the back end could take months". Whoever starts the estimating conversation with, "I think it's 50 days" immediately has an impact on the thinking of the other team members; their estimates have been anchored, i.e. they are all now likely to make at least a subconscious reference to the number 50 in their own estimates. Those who were thinking 100 days are likely to reduce and those who thought 10 are likely to raise. This becomes a particular problem if the 50 is spoken by an influential member of the team when the rest of the team are predominantly thinking higher or lower. Because the remainder of the team have been anchored they may consciously or otherwise fail to express their original unity; in fact they may fail to even discover that they were thinking the same thing. This can be dangerous, resulting in estimates that are influenced by agendas or individual opinions that are not focussed on getting the job done right.
Planning poker exposes the potentially influential team member as being isolated in his or her opinion among the group. It then demands that she or he argue the case against the prevailing opinion. If a group is able to express its unity in this manner they are more likely to have faith in their original estimates. If the influential person has a good case to argue everyone will see sense and follow, but at least the rest of the team won't have been anchored; instead they will have listened to reason.
http://www.planningpoker.com/
http://www.expertware.no/estimationweb/
http://kevinverhoef.nl/poker/
Software development
Software development is the development of a software product...
. It is a variation of the Wideband Delphi
Wideband delphi
The Wideband Delphi estimation method is a consensus-based technique for estimating effort. It derives from the Delphi Method which was developed in the 1940s at the RAND Corporation as a forecasting tool...
method. It is most commonly used in agile software development
Agile software development
Agile software development is a group of software development methodologies based on iterative and incremental development, where requirements and solutions evolve through collaboration between self-organizing, cross-functional teams...
, in particular the Extreme Programming
Extreme Programming
Extreme programming is a software development methodology which is intended to improve software quality and responsiveness to changing customer requirements...
methodology
Methodology
Methodology is generally a guideline for solving a problem, with specificcomponents such as phases, tasks, methods, techniques and tools . It can be defined also as follows:...
.
The method was first described by James Grenning
in 2002 and later popularized by Mike Cohn
Mike Cohn
Mike Cohn is the owner of Mountain Goat Software.He is one of the founders of the and is a Certified Scrum Trainer. He is a trainer on Scrum and agile software process techniques and helped popularize Planning poker which he provides as a free online planning tool...
in the book Agile Estimating and Planning.
Equipment
Planning Poker is based on a list of features to be delivered and several copies of a deck of numbered cards. The feature list, often a list of user storiesUser story
In computer programming a user story is one or more sentences in the everyday or business language of the end user that captures what the user wants to achieve. User stories are used with Agile software development methodologies for the basis of what features that can be implemented...
, describes some software that needs to be developed.
The cards in the deck have numbers on them. A typical deck has cards showing the Fibonacci sequence including a zero: 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89; other decks use similar progressions.
One commercially-available deck uses the sequence: 0, ½, 1, 2, 3, 5, 8, 13, 20, 40, 100, and optionally a ? (unsure) and a coffee cup (I need a break). Some organizations use standard playing cards of Ace, 2, 3, 5, 8 and King. Where King means: "this item is too big or too complicated to estimate." "Throwing a King" ends discussion of the item for the current sprint.
Optionally, an egg timer
Egg timer
An egg-timer is a device the primary function of which is to assist in timing the cooking of eggs. Early designs simply counted down for a specific period of time. Some modern designs are able to time more accurately by depending on water temperature rather than an absolute time...
can be used to limit time spent in discussion of each item.
Procedure
At the estimation meeting, each estimator is given one deck of the cards. All decks have identical sets of cards in them.The meeting proceeds as follows:
- A Moderator, who will not play, chairs the meeting.
- The Product Manager provides a short overview. The team is given an opportunity to ask questions and discuss to clarify assumptions and risks. A summary of the discussion is recorded by the Project Manager.
- Each individual lays a card face down representing their estimate. Units used vary - they can be days duration, ideal days or story points. During discussion, numbers must not be mentioned at all in relation to feature size to avoid anchoringAnchoringAnchoring or focalism is a cognitive bias that describes the common human tendency to rely too heavily, or "anchor," on one trait or piece of information when making decisions.-Background:...
.
- Everyone calls their cards simultaneously by turning them over.
- People with high estimates and low estimates are given a soap boxSoapboxA soapbox is a raised platform on which one stands to make an impromptu speech, often about a political subject. The term originates from the days when speakers would elevate themselves by standing on a wooden crate originally used for shipment of soap or other dry goods from a manufacturer to a...
to offer their justification for their estimate and then discussion continues.
- Repeat the estimation process until a consensus is reached. The developer who was likely to own the deliverable has a large portion of the "consensus vote", although the Moderator can negotiate the consensus.
- An egg timer is used to ensure that discussion is structured; the Moderator or the Project Manager may at any point turn over the egg timer and when it runs out all discussion must cease and another round of poker is played. The structure in the conversation is re-introduced by the soap boxes.
The cards are numbered as they are to account for the fact that the longer an estimate is, the more uncertainty it contains. Thus, if a developer wants to play a 6 he is forced to reconsider and either work through that some of the perceived uncertainty does not exist and play a 5, or accept a conservative estimate accounting for the uncertainty and play an 8.
Planning Poker benefits
Planning Poker is a tool for estimating software development projects. It is a technique that minimizes anchoring by asking each team member to play their estimate card such that it cannot be seen by the other players. After each player has selected a card, all cards are exposed at once.A study by K. Molokken-Ostvold and N.C. Haugen found that estimates obtained through the Planning Poker process were less optimistic and more accurate than estimates obtained through mechanical combination of individual estimates for the same tasks.
Avoid anchoring
Anchoring occurs when a team openly discuss their estimates. A team normally has a mix of conservative and impulsive estimators and there may be people who have agendas; developers are likely to want as much time as they can to do the job and the product owner or customer is likely to want it as quickly as possible.The estimate becomes anchored when the product owner says something like, "I think this is an easy job, I can't see it taking longer than a couple of weeks", or when the developer says something like, "I think we need to be very careful, clearing up the issues we've had in the back end could take months". Whoever starts the estimating conversation with, "I think it's 50 days" immediately has an impact on the thinking of the other team members; their estimates have been anchored, i.e. they are all now likely to make at least a subconscious reference to the number 50 in their own estimates. Those who were thinking 100 days are likely to reduce and those who thought 10 are likely to raise. This becomes a particular problem if the 50 is spoken by an influential member of the team when the rest of the team are predominantly thinking higher or lower. Because the remainder of the team have been anchored they may consciously or otherwise fail to express their original unity; in fact they may fail to even discover that they were thinking the same thing. This can be dangerous, resulting in estimates that are influenced by agendas or individual opinions that are not focussed on getting the job done right.
Planning poker exposes the potentially influential team member as being isolated in his or her opinion among the group. It then demands that she or he argue the case against the prevailing opinion. If a group is able to express its unity in this manner they are more likely to have faith in their original estimates. If the influential person has a good case to argue everyone will see sense and follow, but at least the rest of the team won't have been anchored; instead they will have listened to reason.
Tooling for distributed teams
When teams are not on the same geographical locations, some tools can be used to try get some of the benefits of poker planning.http://www.planningpoker.com/
http://www.expertware.no/estimationweb/
http://kevinverhoef.nl/poker/