https://www.chess.com/article/view/chess-ratings---how-they-work
glick RD tells you how accurate your rating is. the more games you play the smaller the glick RD is. if you don't play games the glick rd increases. it starts out at 350
Is there a formula for it?
I don't know
I think every game you play changes it the same(win, loss, or draw)
The paper by Mark Glickman from 2013 is available online. Wikipedia has the PDF available in its references.