Separating a hockey player’s offensive and defensive contributions is quite difficult. Offensive skill can lead to increased puck possession and therefore improve statistics aimed at measuring defensive performance such as goals or shots allowed. This challenge can be overcome by measuring goals or shots per possession rather than per game, provided a reasonable estimate of possessions is available. Recording when the puck is brought across the blue line makes this transformation possible, enabling a true assessment of performance in the offensive or defensive zone. Surprisingly, a season of data shows no clear separation between players in shot production or suppression; if offensive stars generate more shots per offensive zone possession than fourth line grinders, the difference is small enough to not show up in a single season’s data. Instead, the team’s shot differential – which has been shown to be a strong predictor of wins – is determined almost entirely in the much less-heralded neutral zone. Neutral zone success involves more than getting extra zone entries; since carrying the puck across the blue line generates more than twice as many shots, scoring chances, and goals as dumping the puck in, gaining the zone with possession is a major driver of success.
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