The Pittsburgh Penguins finished the season with a 19.3% success rate on their power play, which was tied for the 8th best in the NHL with Vancouver and New Jersey. This number may seem fine on the surface, but it can be deceiving.
The Pens started out the season on fire on the power play, clicking at around a 45% success rate in November. If it were not for this outrageously good start, the season power play percentage would be a lot lower and likely prompt there to be more discussion as to what went wrong.