My question is simple: You all know that in chat, one can see a reputation score of users below their icon and username (if they posted enough so that there is enough space) or by clicking on the icon to open the info bubble and hovering over the name.
However, this reputation score differs from the score on the parent site!
Which other scores are computed into it additionally?
And how are the scores between the 3 chat servers (chat.stackexchange, chat.stackoverflow, chat.meta.stackexchange) related?