The most complete database of advanced hockey stats
In February 2013 the ratings were updated to a new scale. Instead of 1.00 being an average hockey player, 0 is. One should interpret [Shot,Fenwick,Corsi]HARO ratings to mean that when the player was on the ice his team had x% (where x is his rating) more goals [shots, fenwick, corsi] for than expected (as determined by his quality of team mates and quality of competition). This means that a positive value means more goals were scored than expected and a negative value means less goals were expected. A positive value indicates the player boosted his teams offensive performance while a negative value means he was a drag to his teams offense.
For defensive [Shot,Fenwick,Corsi]HARD ratings the effect is opposite. One should interpret the HARD ratings to mean that when the player is on the ice his team gave up x% (where his rating is x) fewer goals [shots, fenwick, corsi] than expected (as determined by quality of teammates and opposition).
So, a 10 HARO rating indicates the player boosted his teams expected goal scoring rate by 10% and a 10 HARD rating indicates the player reduced his teams expected goals against rate by 10%.
The [Shot,Fenwick,Corsi]HART ratings are simply the average of the HARO and HARD ratings.