How good was the WHA?
In 1985, Bill James’ famous minor-league study determined that the level of pitching in the majors was 18% higher than in AAA. That is, you’d have to discount minor-league hitter’s stats by 18% to predict what they would have done in the major leagues.
In “League Equivalencies,” an article on hockeyanalytics.com, Gabriel Desjardins looks to do the same for hockey.
For instance, Desjardins found all players in the 1972-73 WHA (its inaugural season) who played in the NHL the following year. Those 39 players subsequently scored 46% as many points per game in the NHL as they had in the WHA, and so the “league quality” of the 1972-73 WHA was 0.46.
The WHA’s 0.46 was only slightly higher than the 0.43 for the minor-league AHL that year. “This is not surprising,” Desjardins writes, “since the WHA mined the AHL to fill out its teams.”
The WHA’s quality increased during its life – up to 0.76 the next year, and then irregularly to 0.89 in its final season of 1978-79. By contrast, the AHL stayed in the 0.50 range in the 70s, and is now at 0.45.
The Russian Elite League is the highest-quality non-NHL league at 0.91; the Czech league is second at 0.61, followed by Sweden (0.59) and Finland (0.54).
Desjardins argues, also, that the “real” quality is likely to be higher than the figures he presents, because players moving to the NHL normally get much less power play time than they did in the other leagues. That reduces their point scoring more than just their ability would suggest.
To which I would add: what about playing time? Wouldn’t it also be true that players good enough to be promoted will get less playing time in the NHL than they did in the minors? That would deflate their numbers even more. You’d think this would be a very large factor, at least as large as the power play issue. (On the other hand, you’d think that playing time in high-caliber leagues (like the Russian league) would be less of an issue, since the better the hockey, the more likely the NHL recruit is good enough to get substantial ice time.)
In baseball, of course, we have statistics broken down by plate appearance or outs made, so playing time is accounted for. In hockey, though, without playing time numbers, these results are lower-bound estimates and may be substantially off. But, on that basis, and taking the numbers for what they're worth, this is pretty valuable information.