As I found out, the happiness metric can also be used in a destructive way. When people don't know the context in which a grade is given, they can overreact on those numbers and take actions that make sure team members will give 'political correct' grades in the future.
In search for a good representation I didn't want to use an average grade. All individual grades are too important to get lost in an average. Also a few 1's and 6's could give a very wrongful average of 3,5. So all numbers are important, but they need to be compressed in a 'faster' information radiator.
What I tried, was to make a weather 'backcast' out of it. I found some weather icons on the interwebz and translated the overall histogram to a description of our teams weather conditions. So for example, "Cloudy with here and there some sunshine" (a few 3 and 4's and one 2) or "Sunny with some local thunderstorms" (mostly 2's and one 5). In this way every observer can see what the happiness of this team is and if they want to get more detailed information, they have to ask a team member. This way we can make sure the correct context is given along with the current happiness.
Of course it is a good idea to put the actions that will improve the scores also on the board. You can add: "When we want the sun to shine tomorrow, we need the following improvements:" and then the list of actions. So they are visible for everyone, even (especially) for the 'innocent' bystander.Do you have any improvements?