Trading Off: How Much Possession Can My Team Surrender and Still Win?

Photo by Michael Miller, via Wikimedia Commons; altered by author

Photo by Michael Miller, via Wikimedia Commons; altered by author

Within the continuing discussions over the value of possession metrics, and the veracity of shot quality or shooting talent measures, there’s a point that seems to have slipped through the cracks. While there’s a spectrum of attitudes about possession and shot quality/talent, neither entirely refutes the importance of the other – and with that thinking, it’s worth considering how much you can sacrifice in one and still maintain success by the other. Put more simply, how little can a team possess the puck and still expect to shoot their way to success?

Initially, I know I don’t want to mess around with powerplay and penalty kill time. Generally speaking, few if any teams routinely get an edge from those situations taken together, so I’m hesitant to assume anything about special teams ability beyond what’s demonstrated in even-strength play.

Working with even-strength time, I looked at the last three seasons to help establish the standard deviation of team shooting/save percentage. All the while, I checked to see if it supported my previous assertion that we should expect a little less than one team a year to have “PDO talent” (1% above or below league average).

Satisfied to find the standard deviation (SD) was around 0.7-0.8%, now I can set out to answer the initial question – we’ll allow the SD above and below average to be our markers of above average and below average shooting talent, since once we go above those markers we move into truly rare predictive territory for teams.

The following graph should be read in this way: the x-axis is the possession percentage for Team X. The lines represent the goals-for percentage Team X would have (using the y-axis), given below and above-average shooting. Had I included a line for league-average shooting, Team X with x percentage of possession will likewise have x percentage of goals-for. Team Y that controls 40% of possession but shoots 1 SD above league-average will have roughly 42.5% (actually, 42.6%) of goals-for – the first point on the blue line. I also added a line of the average goals-for% for all playoff teams since 2005-06, which should be considered the sufficient goals-for% to reach the playoffs. For NHL teams, reaching the playoffs is the ultimate achievable goal in any season, as winning the Stanley Cup itself can be strongly influenced by luck.

Tradeoff Between Percentages and Possession

As you can see, a talented shooting team still needs to control half of possession to be projected to make the playoffs, whereas an average shooting team can still, in today’s NHL, take advantage of market inefficiencies for possession players and manage a 52.7% possession team. Why is this important? In a capped league, goal-scoring and goaltending are conspicuous values that often cost dearly, and they are risky due to their variance. Possession tends to be more stable and has less impact on scoring when it fluctuates – all the while being more frequently available at low cost. The trick, of course, is identifying it.

Update: There was a good comment I received that I wanted to address, asking about the 52.7% bar in GF% I set above for making the playoffs. While it seems high for a league where 16 of 30 teams make the playoffs, most of it comes down to confidence – which is to say the shootout adds uncertainty into the mix when you’re looking at teams on the edge of making it. Over the last 3 seasons, roughly 14% of all games were decided by shootout (nearly 25% of all games went to overtime, and nearly 60% of all overtimes went to shootout), and since shootouts are awarding highly variable results with 2 additional points, you pass that uncertainty right over to your projections. Thus, you end up with only 5 teams in the entire league having more regulation losses than overall wins last season (7 in 2012-13 and 2011-12), and the need to outscore by more to be sure you’ll get into the postseason.

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