At the end of the sprintplanning when commititng to the work that will be done in the coming sprint is it a good idea to keep the velocity in mind?
For example when the team wants to commit to a number of user stories estimated as 10 story points while having an average velocity of 7. Should the commitment be adjusted to better match the velocity?
To me it seems Parkinson's law is just about to strike.
Isn't it a better idea to keep the velocity number hidden for the team and only use it to estimate when a certain feautre/story will be done?
It's a good idea to keep velocity in mind at the START of Sprint Planning, not the end.
Velocity is a guide to the Development Team. For example, with a velocity of 15, they will consider taking that total number of Story Points into a Sprint. However, as part of Sprint Planning, they break those stories down in to tasks. It's only at this point, they get a clear picture of what they can do in the upcoming sprint. It may be 10 Story Points, it may be 20 Story Points. Velocity is just a guide.
Can I also add that hiding things from the Development Team is a really bad idea. One of the pillars of Scrum is transparency.
Also, the latest version of the Scrum Guide has dropped all reference to the word 'commitment'. We now, more accurately, use the word 'forecast'.
Hope that helps.