The assessment of the ABA’s prowess has been a recurring inquiry. Despite numerous intense exhibition games between the ABA and NBA, these matchups constitute a limited data set. Our primary focus lies in evaluating the performance of players who participated in both leagues, aiming to discern the respective compeditive level of each league through the connective tissue.
ABA vs NBA Exhibitions and the Super Game
Let’s touch on the interleague exhibitions first. The NBA–ABA All-Star Game represented a showcase of excellence in basketball, orchestrated by the player’s associations of both the National Basketball Association (NBA) and the American Basketball Association (ABA). This exhibition featured a handpicked ensemble of top-tier players from each league engaged in a spirited matchup. Notably, the players undertook the initiative to organize this prestigious event, despite the reservations of team owners, who were staunchly opposed to interleague play in the absence of a league merger. Marketed as the “Supergame,” this extraordinary exhibition unfolded in both 1971 and 1972, leaving an indelible mark on the basketball landscape.
As you can see there was a major foul discrepancy in both games and they did use NBA referees.
As the rivalry progressed, a transformative shift occurred in favor of ABA teams as the league improved its talent. The latter phase witnessed a consistent surge for the ABA, with victory margins of 15-10 (1973), 16-7 (1974), and 31-17 (1975). Ultimately, the ABA clinched triumph in the overall interleague rivalry, securing 79 victories to the NBA’s 76. ABA led 79-76 by the time of the merger.
Individual Players Stats
The easiest and best way to consider impact in our opinion is Player Efficiency Rating. It’s adjusted to the league average of that year and we can see how effective per possession players were in each league and adjust for natural age declines or what point they were in their career. There were many role players, but from what I have read there seemed to be some retribution among coaches in roles when they joined the NBA, so we will focus mainly on the stars. It takes out the politics and NBA coaches that may have punished ABA players early when they came in.
Another reason to focus on PER is because of how much individual statistics from the late ’60s and early ’70s changed in the NBA as well, as how much the NBA was transforming in the 1960’s with racial barriers being removed and roster quota. It gives a more standard number than the raw counting stats where some players were playing 45+ minutes a game, there were tons more rebounds, and the pace was higher. PER averages the impact to that season statistically and gives a platform to compare and adjust for many aspects including the different leagues and rules within them.
Dr. J is the most famous ABA player and one of the more interesting players to judge. Julius Erving made the move to the NBA at 26 years old in the merger, square in his prime. What is interesting is he wasn’t that great from ages 26-28. He hit is prime in the NBA at 29-31 which is atypical. He did show that he could play at a level fairly similar to what he did in the ABA though. If we were only considering his career it would look as if the NBA was a much tougher league to go from a 29 PER to 21 PER in the middle of what is most players’ primes.
It’s hard to read to much from Rick Barry ‘s early career. He was good in the NBA but had to sit out his age 23-year-old season. Players are improving a lot in general from age 22-24. The level of impact per possession was almost identical when he went back to the NBA in his prime though at the age of 28 indicating a similar level of competition.
Zelmo Beaty is a player that benefited statistically moving to the ABA even at an age when most players would be in decline. He went from a beat of 19.1 PER at age 29 in the NBA to 25.2 at 31 in the ABA. That’s odd and would indicate easier competition.
Cliff Hagan is the only player whose career spans time in the 1950’s. He would come out of retirement at the age of 36 and was an All-Star in the early ABA which is widely considered the weaker point and Hagans career would indicate that as well.
David Thompson only played one season in the ABA as a 21 year old rookie, but his impact was as good as they would ever be in the NBA even as a first-year player. This would indicate the league wasn’t as good if a rookie version was similar to what he would be later in the NBA.
Swen Nater was also very similar in both the ABA and NBA.
ABA Teams That Merged
Another interesting area to consider is that four ABA teams merged with the NBA. San Antonio Spurs, the Indiana Pacers, the Denver Nuggets, and the New Jersey Nets. Of those only the NET’s were significantly different the following year after selling the rights to Julius Erving to the 76ers.
ABA 1976
NBA 1977
Spurs
50-34
44-38
Nuggets
60-24
50-32
Pacers
39-54
36-46
These 3 teams with the same core players were also very similar in the NBA.
Conclusion
There were some players that took small haircuts, others were almost identical. We’d estimate overall that the ABA near it’s peak was about 85% as good as the NBA and I think the per-possession impact numbers seem to back that up. It had star power but lacked some of the depth of the NBA. It was a very strong league, likely the strongest non-NBA league that has ever existed.
