Do we need an Impediment List? Yes!
Yes, we need a public impediment list. Every Team does.
One argument against is that all impediments should be eliminated immediately. Yes, if this were possible, this should be done. But I think that assumes an incorrect view of what impediments are.
Yes, it is true some impediments only appear from time to time. If you only get small ones at rate that you can fix them all the same day, then ‘fix immediately’ is the right answer. No list is needed. (Well, honestly, even then I would need a short list.)
But I think we should have a totally different attitude toward impediments.
As with Lean, we should give ourselves the ‘perfection’ challenge. That is, we do not indulge in the fantasy of becoming perfect, but challenge ourselves to strive toward perfection. More concretely, to become the best Scrum Team ever.
So, an impediment is anything that can be improved, leading us to become (we hope) the ‘perfect’ (best) Scrum Team.
Of course, nothing around us, and nothing we do, is perfect. So, everything needs to be improved. Even Michael Phelps can swim a better race.
Then the public impediment list really should be the top 20 things we should fix now. (If we listed everything, we might have 900 items, but in this work, it helps not at all to have a list of 900. Just the top 20 will do for now. A shorted list is more helpful.)
Impediments can be anything — anything — that is keeping the team from being perfect. Missing fun, blockers of stories, people issues, slow CI, managerial interruptions, task-switching, poor organizational incentives, bad user stories, weak PO, waterfall culture, lack of babysitter, Scrum not fully implemented in the organization, lack of urgency for change, bad corporate culture, a culture that requires hiding any ‘failure’, etc, etc, etc. Anything. Of any type.
Also, some impediments are quite difficult to fix. Might take time. Might need to be broken into parts.
In my experience, many obvious impediments are begging to be put on the list, but people pretend the ‘elephant’ is not there. In part, because no one gave them the notion to start a list.
Lastly… Some complain, rightly in some cases, that an impediment list implies inaction on the impediments. Of course, the purpose of the list is NOT to stop action on fixing or ameliorating them. The list is supposed to help us attack the impediments.
So, have a list. Attack them. Aggressively.