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Wideband Delphi and Planning Poker Estimation Techniques

29 April 2016

Vyom Bharadwaj
Shiksha Infotech Private Limited

Many teams use different estimation techniques from the Agile framework. Two that I have found extremely helpful are Wideband Delphi and Planning Poker.

Wideband Delphi

Wideband Delphi is a group-based estimation approach. A panel of experts submits estimates anonymously so that no one knows which estimate belongs to whom. This anonymous approach produces an improved estimate by minimizing the likelihood of people agreeing with a prominent viewpoint (also known as the bandwagon effect) and also by minimizing the likelihood of people being influenced by the ideas of experts or superiors rather than judging the ideas on their own (also known as the halo effect).

A Wideband Delphi estimation meeting starts with an effort to define the problem. The group breaks down the project or large problem into manageable chunks. Consequently, the group develops the estimation over several meetings instead of estimating the whole project in one meeting. The team creates a problem specification, identifies the assumptions and constraints, and outlines the process for subsequent rounds of estimation.

Before creating the estimates, the team reads the problem specification and has an opportunity to raise and discuss qualification questions. A facilitator gathers the estimates and plots them on a chart, without identifying which estimate is from which estimator. The group participants then discuss the different tasks and any assumptions or other significant factors that influenced their estimates before repeating the estimation process. After several rounds, the team starts to see more consensus around the estimates.

Wideband Delphi is iterative, adaptive, and collaborative.

Planning Poker

Planning Poker® combines all the essential elements of Wideband Delphi but in a faster and more collaborative process. It uses playing cards. The numbers on the cards are often based on the Fibonacci sequence. These numbers represent the story-sizing units that can be translated as either developer days or story points.

Each Planning Poker participant is given a set of cards. After the cards are distributed to all the team members, the product owner or the customer, who acts as a moderator, reads the user story and then the group discusses it briefly. The team member or the estimator then selects a card to represent his or her estimate for the user story. All the participants turn over their cards simultaneously so that everyone can see the numbers. The process is repeated (i.e., everyone picks up their card and estimates again). Planning Poker is thus a consensus-based approach to estimation.

Like Wideband Delphi, Planning Poker consists of multiple iterations of estimation (when needed). That is, it requires participants to submit estimates at the same time, thus nullifying the bandwagon and halo effects, and it allows the group to converge on supported estimates or build a consensus over estimates.

To conclude, Planning Poker is based on the Wideband Delphi estimation technique, yet it is a fast and an enjoyable estimation technique used in Agile and Scrum.

Opinions represent those of the author and not of Scrum Alliance. The sharing of member-contributed content on this site does not imply endorsement of specific Scrum methods or practices beyond those taught by Scrum Alliance Certified Trainers and Coaches.

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