PER and WS/48 are stats we routinely use in comparing players of different eras. As such, what became a tiny bit of a concern for me are the trends we see in certain eras where no one appears to distance themselves very far from the pack (as measured by PER or WS/48), relative to what is customary in recent years.
This is most noticeable for a few years in the late 60’s and very early 70’s, though it’s also noticeable throughout the 70’s---where no one (except Kareem) even approaches the PER and WS/48 levels we routinely see multiple players hit in recent years---as well as the early 80’s.
Just a few examples of what I’m talking about:
*in ‘69 Jerry West had the league’s best PER, at 22.32…….this would have been well outside the top 10 last year.
**the league leaders in both ‘68 and ‘70 were both <25 PER’s, and would have been good for only 10th in the league last year. In '67 the league leading PER was 26.51 (would have been 5th last year).
***in ‘71, ‘72, ‘77-’79, no one aside from Kareem managed a PER >25 (in four of those years no one else managed >24).
****in ‘69 Willis Reed had the league’s best WS/48 at .2268 (good enough for only 8th last season).
*****in ‘70 Walt Frazier had the league’s best WS/48 at .2361 (good enough for 7th last season).
******The league best WS/48 every year of the early 80’s would have only been good enough for somewhere around 7th-9th place last year. Most of the league-best PER’s in those same years would do about the same.
And so on….
There may be a number of explanations for these trends. I’ll sport a few:
1) Perhaps there simply weren’t any players good enough (except for Kareem) to distance themselves from the mean as much as we’ve become accustomed to. It’s possible, and as such the data I’ll share below may simply be punishing players for so exceeding their peers and rewarding others for NOT exceeding their peers as much. Though personally I’m a little skeptical of this explanation (at least as a sole explanation), particularly for the late 60’s (and circa-1970): note that Wilt is still in his prime thru the late 60’s (many consider ‘67 his peak, in fact); West peaks somewhere in ‘65-’67 according to most, and is in his prime at least thru ‘72; Robertson is in his prime thru ‘68 at least. Players like Willis Reed and Walt Frazier are hitting their primes (or peaks) around the time Robertson and Wilt are exiting their primes.
2) Perhaps there were factors pertaining to game philosophy/game-play and/or rules which hindered an elite player’s ability to distance himself a great deal from the herd. EDIT: I'm starting to think pace might be one of these factors, as the seasons with the greatest parity tend to be around the years with the fastest league-avg pace. It's long been a "criticism" or comment regarding using Per 100 Possession numbers to compare stats across eras, as people have noted that a superstar's shot attempts [for example] do NOT increase in a linear fashion with team pace (it seems that past a certain pace threshold, there will [necessarily] be a certain degree of "shot indiscretion" [as to who is taking said shots] in order to maintain that fast pace. This will DIRECTLY EFFECT [read: lower] THE LEAGUE-BEST PLAYER EFFICIENCY RATINGS in particular.
3) Stars were somewhat routinely playing larger minutes in those days; as these are rate metrics, perhaps simple fatigue is a factor in reducing the high-end PER's or WS/48's.
4) Perhaps the “average” and maybe more so the “below average” player in some of these years were generally better (relative to era) than the average or below average players in more recent years. For instance, maybe teams circa-1970 didn’t have to populate the last few roster spots with true “garbage time” players.
This is the theory that it presently intriguing me, fwiw. Note, for instance, that the NBA expanded by 70%!! (from 10 teams to 17 teams) in a span of just four years between the ‘67 season and the ‘71 season---the most rapid expansion in league history---in spite of the fact that these years EXACTLY coincide with the emergence of a competing splinter league (the ABA). In fact, the majority of that expansion occurred AFTER the ABA was beginning to make an imprint and attract relevant talents. Yet even though the ABA was attracting these relevant talents, the NBA still felt there was a sufficient untapped talent pool to justify continued expansion in these years. If this theory is at all correct, that would indeed suggest that the lower tier talents in the league during the late 60’s (fading into the early 70’s) were better (relative to era anyway) than the lower tier talents in the league presently…..which would make the mean/average player (as measured by PER or WS/48) more formidable, and thus more difficult to greatly exceed.
Idk, just postulating; feel free to discuss.
At any rate, thinking on this stuff persuaded me to calculate some rough standard deviations for both PER and WS/48 for each season going back to ‘52. And then from that, I went on to create a scaled model for PER and WS/48 (similar I suppose to the scaled RAPM’s that Doc figured up). And just to make sure I wasn’t overly skewing the results, I did not sample only higher percentile players when calculating the standard deviations. I also sampled players from percentiles near the mean, as well as percentiles well below the mean.
I thought some may be interested in seeing the top 100 or so greatest scaled rs PER’s and WS/48’s of all-time. (I’ve run nearly 170 thoughtfully selected player seasons, so I’m pretty sure I didn’t miss anyone who would crack the following lists).
I’ll get around to posting the best scaled playoff PER’s and WS/48’s soon. EDIT: Oh, and I'll also try to get around to posting a list for ABA's scaled PER and WS/48.
Will comment more once people have had a chance to digest.
EDIT: Updated to include ABA player seasons (highlighted in violet-blue). UPDATED to include '20 season.
Top 100(ish) Scaled rs PER’s
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Top 100(ish) Scaled rs WS/48’s
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