This page analyzes icings by teams and the result following the icings. Four different results are distinguished:
A goal is scored within 30 seconds against the icing team. In this case the icing is awarded -10 points.
A penalty is committed within 30 seconds by the icing team. That's worth -2 points.
Another icing by the same team happens within 30 seconds. That's zero points.
Any other outcome that implies a lineup change became possible again. In this case the icing is awarded one point and is called a good one.
The score of teams against whom the puck was iced is calculated in the same way, but the order is reversed. Thus, if a team scored 10 goals and forced 10 penalties and 10 icings, while 200 icings by other teams turned to be "good", its "against" score is (200 - 10*10 - 10*2 - 10*0)/230*100 = 34.78. The lower the score, the more dangerous is to ice the puck against that team.