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The planning poker method is most effective when an expert is engaged in the estimation and when the team has previous experience with similar tasks. Planning poker was introduced by Grenning in 2002; the technique combines expert opinion, analogy, and disaggregation into a quick and reliable estimation method. The goal of planning poker is to arrive at an estimation that will withstand future scrutiny. Planning poker is an incremental team-based method that collectively analyzes requirements and determines an estimation. The distinct difference between planning poker and Delphi is that not all group members in a planning poker session are required to be experts.
Planning Poker, also known as Scrum Poker, is a consensus-based estimation technique used in Agile project management and Scrum, often for estimating the effort required for development goals. This technique is most commonly used to estimate the complexity of development goals in terms of "story points," though it can be used with any other units of estimation, like time.
Here's how Planning Poker works:
Card Distribution: Each member of the development team, excluding the Scrum Master and Product Owner, is given a set of cards. Each card has a value corresponding to a valid point in the estimation scale, usually a modified Fibonacci sequence (0, 1, 2, 3, 5, 8, 13, 21, 34, etc.).
Backlog Item Presentation: The Product Owner presents an item from the product backlog that needs to be estimated. They describe what the goal of the item is, the work it would involve, etc.
Discussion: Team members discuss the backlog item, asking questions and clarifying any points of uncertainty. This discussion continues until everyone has a clear understanding of what the work involves.
Individual Estimation: Each team member privately selects a card that represents their estimate of the effort required to complete the item. It's important that team members do not influence each other's estimates, hence the selection is made privately.
Card Reveal: All team members simultaneously reveal their selected cards.
Discussion of Estimates: If there is a significant discrepancy in the estimates (for example, if some team members have selected 3 points and others have selected 8 points), a discussion is held to understand the reasons behind the differing estimates.
Repeat Estimation Process: After discussing the reasons for discrepancies, the estimation process (steps 4 to 6) is repeated until a consensus is reached.
Planning Poker leverages the wisdom of the whole team, helps to uncover hidden complexities, and minimizes the chances of a single person's perspective or bias dominating the estimation process. It is also a useful tool for fostering discussion and understanding about the backlog items within the team.