In order for the Team to provide a Commitment they need some way of estimating the work effort of the Product Backlog Items. To help teams determine their commitment level Scrum employs a rather unique way of estimating through a technique known as ‘Planning Poker’. Basically it works like this:
1. Each Team member (except the Product Owner) is given a deck of Planning Poker cards (that carry a value of between 0 and 200).
2. The team reviews each product backlog item and decides which is the smallest / least complicated item and assigns it a value (e.g. 2-points). It really doesn’t matter what units you use (it could be popsicle sticks for all that matters) as the estimates are all relative to each other.
3. Then, starting from the top the Team selects the first item from the product backlog
4. Each team members selects a card that they feel represents the effort that will be sufficient (on average) to complete the item to the Team’s definition of done by comparing it relative to the 2-pointer.
5. Once everyone has estimated, they each turn their cards face up. The person who estimated the highest is asked to explain their reasoning. The same for the lowest. The Product Owner, while not participating in the estimation exercise is available to provide clarity, examples, explanations, and elaborations of the item being estimated.
6. This estimation process is repeated until a consensus is reached for each item as the team goes further down the list. The estimation process is time-boxed (usually 1-hour).7.
At the end the points (or popsicle sticks) are added up and allocated based on the length of sprint (e.g. 2-weeks) and by the average number of hours per day a person can devote to the sprint (e.g. 4-6 hours accounting for email, meetings, breaks). This becomes the sprint goal. The Product Owner is invited but only in the capacity of clarifying, explaining, and expanding the Product Backlog item (User Story) to assist in the estimation effort and not to provide comment on the estimates being made. The Planning Poker exercise is usually facilitated by the ScrumMaster