In some of the biggest debates about top NHL draft prospects in recent years, one trend has been common among them. It existed in Connor McDavid vs. Jack Eichel, Taylor Hall vs. Tyler Seguin, Nathan MacKinnon vs. Seth Jones, Aaron Ekblad vs. Sam Reinhart and this draft season with Auston Matthews vs. Patrik Laine. One of these prospects played a full extra season of hockey prior to being drafted due to having a late birthdate, and the other didn’t.
Since I started doing work in the hockey prospect arena, the issue of late-birthdate prospects confounded me. After years of dealing with prospects, and doing recent research on the matter, I am convinced it is one of the most important quantitative factors that can go into prospect evaluations.
Yet whether in the industry, or in public discussions in the media, I do not feel like this variable gets discussed enough. Not only is this variable under-appreciated, but the lack of attention may be cause for serious errors in evaluations of draft prospects.
Hockey’s unique rule
The late-birthdate prospect issue is one that is unique to hockey. Players born after Sept. 15 through the end of December in a particular calendar year have their NHL draft eligibility pushed back a season. This prevents minors from playing in NHL camps with adults. Football is the most stringent of the other major sports, as players must be three years removed from high school to qualify for the draft. Basketball’s cutoff is 19 years of age, and while baseball allows high school players to declare eligibility for the draft, the nature of the sport dictates that they never have to worry about playing with big-leaguers at that age.
This may seem like a small difference, but it can have significant consequences on the draft. The main effect is that there is a group of first-year draft-eligible players who have an entire extra season of playing experience compared to their younger counterparts. CHL players get a third season, Americans get a freshman season in college, and Europeans may get a full season of hockey played against professionals.
Recent examples
I’ve been asked to compare Toronto’s William Nylander against Colorado’s Mikko Rantanen this season, both of whom are both lighting up the AHL. The argument for Rantanen is that he is one season removed from his draft and posting similar numbers to Nylander, who is two seasons removed from his. However, they are only five months apart and belong to the same birth year, due to Rantanen being a late birth date.
When I ranked Nathan MacKinnon over Jack Eichel in my top 30 prospects of the past three years, I got many interesting comments (mostly from the Buffalo area), but that was an extreme example of birth date. MacKinnon was in the absolute youngest range in his class, and Eichel was one of the oldest. Eichel had a fantastic season with Boston University -- one of the best ever for a college freshman -- and was one of the best Americans at the IIHF World Championship last spring. But during that same time frame, due to his being a full season younger than Eichel when he was drafted, MacKinnon won the Calder Trophy as the league’s top rookie.
Some may argue this is making a big deal out of nothing, that we’re simply discussing a matter of months. But at that young an age, those months are critical. The difference between a 24- and 25-year-old in the NHL isn’t huge, but for young players, the difference between 17, 18 and 19 is enormous. Players take vast leaps in physical progression as their bodies mature, and those few extra months of playing experience can be a significant extra proportion of playing time compared to their counterparts. Just look at the huge leaps players make in the CHL between their 16-, 17- and 18-year-old seasons.
Many NHL people understand this issue. It is common occurrence in the industry to hear prospects referred to with “late” before their birth year. However, not all evaluators see it that way. I’ve heard some hockey people say they don’t adjust for birth month, grouping all players together in one draft class as equal.
Calculating the impact
So how aware are NHL teams about the effects of birth month on prospect projections, and how much impact does it have in terms of doing an evaluation?
I’m not sure answering the first question would reveal much. Scouts often talk about “projecting” prospects, focusing on abilities rather than pure output, as well as how a player has looked in recent games. I believe many NHL people take that line of thinking seriously and try to implement it. However, there may be some recency bias in how they draft players, placing too much importance on recent performance.
To have a look at production for the late-birthdate vs. non-late-birthdate prospects, I compiled all first-year eligible skaters drafted from 1990-2010, and split them up into late-birthdate and non-late-birthdate prospects. I then took the total production from each individual draft slot in the top 210 and sorted them by points per game. I excluded all pick numbers where both categories were not represented, which left about 195 pick slots. Here are the results.
The results were about the same no matter how I sliced it. Sums or averages, forwards or defense, CHL or non-CHL. There are two interesting takeaways:
The first-year eligible late-birthdate prospects are being overvalued at the draft relative to their younger, less experienced counterparts. This is a historical look, so who knows what happens tomorrow, but based on this 20-year time frame, older prospects have been taken higher in the draft than they should have been, nearly across the spectrum. The gap may not seem huge, but a 0.10 gap in points per game over a 300-game span adds up quickly.
This effect does not seem to occur at the very top of the draft board. Think John Tavares, Victor Hedman, Alex Ovechkin, Eric Staal and Patrick Kane among many others as examples of elite late-birthdate prospects. For these older players, who have been scouted closely for years, scouts seemed to have zeroed in the right value point for them. This leads me to believe teams aren’t misidentifying who the NHL talents are. Instead, they are valuing older players with lower offensive upside slightly higher than they should be.
With that known, I then turned to how much someone should adjust for birth date in an evaluation. This was inspired by hockey historian Iain Fyffe’s research five years ago on the same issue.
Using the 1990-2010 draft class span, I took every CHL forward who played at least 20 games, was a first-year draft-eligible player, and had a points-per-game rate between 1.0 and 1.5 in their draft season, adjusted for league strength (thanks to Helen Cruz and Vancouver Giants analyst Rhys Jessop for help with that.) Using this list batch of 190 players, I sorted those results by birth month and NHL points per game. I used averages instead of totals, because the sample size was so small that elite NHL players skewed the numbers.
The swing here between a late-birthdate prospect and non-late-birthdate prospect can be nearly .30 points per game, which should raise some eyebrows. While the correlation between birth month and NHL scoring rates isn't entirely linear, one thing that sticks out is that the oldest of the late-birthdate players in the study finished with the lowest average rate, while the highest average rates belong to some of the youngest in each class.
The 2016 draft class
To make all of this relevant, here’s a quick rundown of first-year eligible players in this year’s draft class who fall under the category of late-birthdate prospects:
Projected No. 1 overall pick Auston Matthews
Projected first-round picks Matthew Tkachuk, Julien Gauthier, Charlie McAvoy, Luke Kunin and Rasmus Asplund
Projected second-round picks Carl Grundstrom, Nathan Bastian, Zach Sawchenko, Lucas Johansen and Simon Stransky
It’s certainly relevant when discussing Matthews vs. Patrik Laine, the latter of whom is seven months younger, and has one full season less of hockey experience. When I recently ranked Clayton Keller No. 4 overall over Matthew Tkachuk at No. 5, I got some blowback. But Keller is eight months younger than Tkachuk, and has arguably been more impressive with the USNTDP than Tkachuk was when he was there last season.
Do I think this is the absolute end-all, be-all for approaching an individual draft class? Of course not. However, as another example, failure to incorporate this line of thought into a Tkachuk (December 1997) vs. Alexander Nylander (March 1998) analysis is the same as ignoring a World Junior Championship performance, or ignoring a size discrepancy, or ignoring a character analysis. You won’t lose insight altogether, but you’re missing some pretty important predictive information.
It could make the Matthews (September 1996) vs. Laine (April 1997) decision tougher as well. There is not a full year’s difference between them, but there’s an argument to be made that Laine has been more impressive this season than Matthews was at the same point last season. Granted, Matthews has done nothing but impress in his performances this season, but the factor is there.
Conclusion
Analyzing teenage prospects comes down to a matter of fine details, and one fine detail has sometimes been missed: The month that a prospect was born.
The prospects that have an extra season of playing time are significantly ahead of their younger draft classmates, and should be assessed with that in mind.