On Twitter recently, I was told that I shouldn’t be writing a hockey blog simply because I referred to Taylor Hall as an elite player. I couldn’t let this ironic opportunity pass me by, so here is why, from an analytics perspective, I think Hall is an elite player.
First, let me define elite player. Statistically, I define elite as any measure that is about 2 standard deviations above the mean, or in simpler terms, 98% better than all other comparison players. Typically, we would compare forwards with forwards, and defensemen with defense. Also possible to be more specific by comparing centers and wingers separately, but in presenting evidence for Hall, I’m going long and comparing him to all forwards.
Second, what would be a reasonable time-line? I think 4 seasons gives pretty reliable measurement over time. Goal-scoring can be highly variable from season to season because of shooting percentage variability, but after 4 seasons, shooting percentage approaches a “true” or reliable value.
Third, I focus on even-strength (5v5) metrics because 80% of the game is determined at 5v5 and moreover, it is more challenging to produce as compared to the power-play. These 2 factors, then, would be my basis for arguing that for 5v5 represents a more accurate assessment of a player’s ability.
Fourth, what measures would I use as evidence, that is, what are nuts and bolts of an elite player? The 6 measures (5v5; per 60 minutes) are :
- Goals
- Primary Assists
- Primary Points
- Points
- GF% Relative-to-Team (i.e., team’s goal differential with the player on the ice vs. the team’s average goal differential)
- Individual Proportion of Points
Why primary, but not secondary assists? Recent analysis has shown that Primary Assists are repeatable over time, but Secondary are more random. Thus, primary Assists tend to represent a player’s “true” skill as a playmaker. This then, in theory, affects which points are the more reliable points. By excluding secondary assists, we are left with primary points (goals + primary assists). But does that mean secondary assists are meaningless in assessing a player’s ability? I would argue, no.
In the sample (297 forwards, 2012-16), I computed the correlation between primary & secondary assists and found a statistically significant correlation of .49 (p < .001). This moderate correlation suggests to me that players who are better playmakers–because they are likely strong passers in general–tend to have more secondary assists. The points metric, then, is included because it captures three meaningful metrics: goals, primary assists, & secondary assists. The whole is greater than the sum of the individual parts, or something like that.
Finally, the last 2 metrics attempt to the player’s impact on the team. GF% Relative-to-Team answers the question: Relative to his teammates, how well does the team do in outscoring the opposition with the player on the ice? Individual percentage of points tells us the what proportion of points is the player directly involved in when the team scores.
So how many players are in the 98th percentile of any given metric? Using the last 4 seasons, including the current (2012-16), with players over 2000 minutes of ice-time there are 297 forwards, which represents the top-9 forwards of all teams (i.e., 270 players). There is a few ways to compute 98th percentile. The simplest way, which I think makes intuitive sense for the non-statistical-minded person, is to look at the upper 2% of players on any metric. Thus 2% X 297 = 6. In short, we want to know the top-6 players on a metric.
So how does Hall rank in each metric? I present the rank plus the metric in parentheses (per 60 minutes; except where otherwise noted):
- Goals: 58th (0.82)
- Primary Assists: 3rd (1.68)
- Primary Points: 7th (1.91)
- Points: 3rd (2.5)
- GF% RelTM 17th (+9.2%)
- IPP 1st (87.6%)
Thus, in 3 of 6 metrics, Hall is in the upper 2% of the league: Primary Assists, Points, & Individual Proportion of Points. In fact, he ranks 1st overall in his proportional contribution to the team’s points while on the ice. His Primary Points rank of 7th is so close that I might as well call it upper 2%. So that’s 4 metrics that rank as elite (as I have defined it). Next, he ranks 17th in GF% RelTM, which is about 95th percentile, and 58th in goals, which is about 80th percentile.
Overall, 4 out 6 of Hall’s metrics are at the elite level, the GF% RelTM metric has Hall performing better than 95% of forwards, and the goal metric has him scoring at a rate better than 80% of forwards. For me, I think that’s a pretty solid case for being an elite forward. Others may disagree, but if you’re going to post your disagreement, I would kindly ask for your rationale. (Remember, the measures do not include the power-play.)
Thanks for reading and please post your comments below.
Walter
Data courtesy of David Johnson’s stats.hockeyanalysis.com
