What Does Number 13 Refers to in Planning Poker?

Planning poker, also called Scrum poker, is a consensus-based, gamified technique for estimating, mostly used to estimate effort or relative size of development goals in software development. In planning poker, members of the group make estimates by playing numbered cards face-down to the table, instead of speaking them aloud.

The cards are revealed, and the estimates are then discussed. By hiding the estimates until they are all revealed at once, the process reduces the influence of anchoring, where the first number spoken “anchors” the subsequent discussion.

PRO TIP:In planning poker, the number 13 is a placeholder used when there are no other cards that accurately describe the complexity of a task. It allows for flexibility in the estimation process and can be replaced with an appropriate number once more information is available.

The numbers on the cards refer to the Fibonacci sequence. The reason for this is that estimation is very difficult when dealing with uncertainty, and using a sequence that gets progressively larger allows for more accurate estimates.

The largest number in the sequence, 13, is reserved for “outliers” – items that are significantly larger or smaller than everything else being estimated. This allows for more accurate estimation by forcing people to think about whether an item is really an outlier or not.

While there are many different ways to estimate in software development, planning poker is a popular technique that can be used to get relatively accurate estimates quickly. It is important to remember that no estimation technique is perfect, and that all estimates should be considered as ballpark figures only.