From the article:
Last year, Toronto did not look good in the Corsi standings. In 5-on-5 situations, they took only 44.1 percent of the shots (meaning their opposition took the other 55.9 percent). That was worst in the NHL.
So how did the Leafs win so many games, finishing in the top half of the standings? Even though they took few shots, the shots they did take went in at an exceptionally high rate. The Leafs had a 10.56% shooting percentage (goals divided by shots on goal), the highest in the league. No other team was over 10. The league average was roughly 8, with a standard deviation of roughly 1, so the Leafs were well over 2 SDs above the mean.
Is the 10.56% shooting percentage referred to in the second quoted paragraph based on goals/shots directed at net in 5 on 5 situations? If not, what was the Leafs shooting percentage in that situation? That is the number that would be most meaningful in discussing the 44.1% 5-on-5 Corsi referenced in the first quoted paragraph.
Also, how much does the Leaf's success in non 5-on-5 situations explain their overall success despite the 44.1% 5-on-5 Corsi? A quick glance at the NHL team goals for and goals against stats pages shows that their goal differential was a relatively pedestrian +5 (105 vs 100) in 5-on-5, but an impressive +12 (31-19) in PP situations, and +2 (3-1) in 4-on-4 situations.
In other words, 5 on 5 they scored 5% more goals than the opposition, but 5 on 4, 5 on 3, 4 on 3, and 4 on 4 they scored 70% more goals than the opposition (34 to 20). In actual goals instead of percentages, they were plus 5 in the former situation and plus 14 in the latter.
That impressive non 5-on-5 performance probably goes a long way in explaining their success, leaving less to be explained by 5 on 5 luck vs. 5 on 5 quality shot skill.