Once in a while I encounter teams that do poker planning and that includes the Product Owner or even Scrum Master. But that is not how it supposed to be!
Poker planning is a method to plan the amount of work to be done before a team implements a small functional increment or Product Backlog Item (PBI). And who is implementing this PBI?….Yes, indeed, the development team. Now this is where Scrum becomes a bit fuzzy. There are two entities called team within Scrum, the Scrum team and the Development team. Sometimes both called team. So I do understand where the confusion comes from, but we have to keep in mind what the purpose of poker planning is. It is for estimating the work to be done to implement a PBI that is ready to be picked up in the sprint. The Product owner is not doing the implementation of a PBI.
The Product Owner is the one that is accountable for the ROI, thus creating the most valuable PBI’s from the backlog for the next sprint. So he/she will be very busy getting enough information to get the most important PBI’s ready, especially with high performance teams this is a hell of a job to do (but a very rewarding one). Besides getting things ready, he/she will be very busy doing stakeholder management to determine the PBI’s with the highest value. Thus he/she will not take part in actually implementing it. This is why only the development team should take part in the poker planning.
The development team is putting all their effort in the implementation of the PBI to get it done. They have their meat in the product so to speak. They use the poker planning to estimate the relative size of a PBI with respect to previous PBI’s they estimated. It is very important to let them do the estimation of the PBI’s because it will influence their velocity. We don’t want to interfere with this process because it’ll influence the rhythm, or one piece continuous flow of the team. What we’ll get back if we back off will be a predictable team, and is that not what we like to have most of all, predictability?