Imagine that you have been made the General Manager of a NHL Team.

One of your key jobs is evaluating player performance on both your team and also other teams within the NHL. In addition, you have evaluate the performance of players in the AHL as well as the ECHL, the CHL, NCAA, Swedish, Finnish, German, Swiss, Czech, Slovak leagues, the KHL, Tier Two Junior Hockey, US High School Hockey, and keep an ear out for players in other lesser leagues. Some of that work is obviously left to scouts, but you as a GM will be responsible to some extent in directing your scouts to give you the information that you need to make informed decisions.

Also, you will have at your disposal the resources to acquire any stat that you deem important. For instance, the first thing I would do as a GM of a team would be to get a whole bunch of University students on non-paid summer internships(preferably BSc in Stats majors) watching tons and tons of video extracting accurate stats from as many teams and leagues as I could source.

Acknowledging that in hockey, as a multi-faceted game involves several different components from defensive zone play to special teams to shoot-outs. Thus many statistics would be important.