Goalscoring Metrics: Goals Per Season

In the media, strikers are often ranked by the number of goals they score in a season (“Goals per Season”). According to this metric, the best striker is simply the one who scores the most goals. 
However, this approach doesn’t take into account two important factors:

•Some strikers get more playing time than others

•Some strikers are designated penalty takers

For these seasons, “Goals per Season” isn’t a very good measure of a striker’s skill. 
To correct for the limitations of the “Goals per Season” metric, technical scouts look instead at the number of non-penalty scored by a striker per 90 minutes payed. The metric is referred to as NPG/90.  Goalscoring Metrics: NPG/90 Here’s how NPG/90 is calculated.

First, we up the total number of goals the players scored. We ignore goals scored from penalties. 
Next, we divide the figure by the total numbers the players spent on the pitch:
This tells us how many goals the player scored per minute of playing time. Next, we multiply this figure by 90 to find out how many goals the player scored per match:
This figure is the player’s NPG/90 metric.