From my understanding, planning poker involves the development team or the executors of the project and the project manager or the project owner. I recently had a debate with our project manager on this issue about whether or not to include a client in this activity.
Here are the arguments for both sides:
I advocated against this because i feel if a client is in the room there is the possibility of changing our estimates and making them more optimistic than they are because the client is in the room.
On the other hand, if the client is in the room they could provide and clear up requirements and let them understand the process and the value it could provide.
Therefore, my question is the following. In the best interests of estimation accuracy (i know it is almost impossible to be accurate), which it be best to include a client on this activity or preclude them?
edit by said PM: Should be noted that in this case the client is both the project owner and sponsor.