Effects of League Expansion on League Strength?

[ty 4191]

Taking an average over a 10 year span is pointless, because those are completely different teams. The only thing that's the same is the franchise....

The way you're using statistics makes no sense.

The thread is about LEAGUE strength. So yes, franchise records are what matter over a statistically significant sample of years.

1979-1988 is before 6 bad or terrible expansion teams were added to the league, 1989-1998 was during and right afterwards.

The percentage of teams below .400, relatively speaking, is illustrative of how much more balanced the 80's were than the 90's.

And, do you think it's a coincidence that the NBA hasn't expanded once since 2004, and that only 3 out of 30 teams are below .400. overall, during that entire timeframe? And, also, during the last 10 years?

Expansion destroys league quality and it destroys competitive balance.

[penbeast0]

Actually, it looks like that table shows star stats being greatly inflated twice, once in the 80s and again in the 2020 period. It doesn't show that the inflation correlates in any significant way to expansion although you can see the expected jumps in the 90 and 96 expansions (which go away); I would guess it's more about coaching styles and building around starpower.

[magicman1978]

Thank you, that's interesting and unexpected
Seems weird intuitively but it looks like no significant stat inflation due to expansion. Maybe stars were playing down to competition? Or worse players were making up for it by being less lazy on defense? Star players just happening to be lower quality on 3 separate expansion occasions is a very unlikely explanation.

Reagrding today's stat inflation (or inflation of more guys with great stats) it's probably mostly in per minute stats because stars play less and can play harder over short stretches and have higher usage/dominance because of less in-game rest needed.
But who knows, guess things are just complicated

Just spitballing here, but I think that freedom of movement rules of today coupled with better coaching (due to analytics) are enabling highly skilled players to differentiate themselves more from the mean.

I had no idea what I was going to get when I was looking at the data, but I had an assumption (A better analysis would have been to look at how expansion impacted certain players, but that would take more time that I have). Your theory seemed to be correct when I looked at the year pre-expansion vs the expansion year (in 90 and 96), but when looking at the subsequent years, they normalized. Which wouldn't make sense if the issue was just the talent level. So the theory I am going with is that the rules at the time allowed less talented/skilled players to bring the more talented ones down to their level.

[RCM88x]

In my opinion, SRS, winning %, etc... are not what matters in discussing league strength. Average talent per player (or team) is what matters. Let me make a simple analogy...

Imagine I have an apple orchard with 10 trees, that supply 10 customers, divided up equally ever year. Each year I plant one new tree to supply those 10 customers with more apples.

However, after 2 years I have 2 new customers. Now I have 12 trees for 12 customers. So obviously each customer is going to get on average worse apples than they did the year before, when I had 11 trees for 10 customers.

If you just look at the relative apple quality of each customer within each year (SRS etc...), you won't realize that the quality/quantity of apples is changing from year to year.

SRS doesn't tell you the actual quality of the team in a vacuum, it just tells you that quality relative to the rest of the teams, aka the league. Expansion doesn't mean rings are weaker because there were more bad teams, it means they are weaker because that same pool of players/coaches suddenly is spread thinner.

Anyways, I'm sure that's obvious to some but when it comes to debates about "league strength" specifically in relation to expansion, common team rating metrics are just not useful in my opinion.

[ty 4191]

1 player exceeded 20 Win Shares from 1979-1988. The average of the top 15 player seasons in Win Shares was 15.

4 players exceeded 20 Win Shares in a season from 1989-1988. The average of the top 15 player seasons was 18.

[DQuinn1575]

1 player exceeded 20 Win Shares from 1979-1988. The average of the top 15 player seasons in Win Shares was 15.

4 players exceeded 20 Win Shares in a season from 1989-1988. The average of the top 15 player seasons was 18.

so only 6 players ever exceeded 20 win shares-
MIkan
Wilt
LeBron
Jordan
Oscar
Jabbar

and two, LeBron and Oscar have 1, so there will be concentration in time periods when the other 4 played.
The timing of the careers of maybe the 6 most dominant statistically players of all-time says almost nothing about league quality.

[ty 4191]

so only 6 players ever exceeded 20 win shares-
MIkan
Wilt
LeBron
Jordan
Oscar
Jabbar

and two, LeBron and Oscar have 1, so there will be concentration in time periods when the other 4 played.
The timing of the careers of maybe the 6 most dominant statistically players of all-time says almost nothing about league quality.

Ok.

So use the standard deviation of Win Shares, then. Same results.

Hell of a LOT easier to dominate when 35% of the teams are under .400 (2 under .300) versus 17% under .400 (0 under .300).

1979-1988 versus 1989-1998.

[magicman1978]

Jordan was the only player during the 89-98 period that exceeded 20 WS. However, his total WS and PER peaked prior to expansion. There's no statistical evidence I can see that supports expansion as a reason he maintained those numbers through his prime.

[ty 4191]

Winning Percentage Standard Deviation:

1957-1966 (pre Major Expansion):
Standard Deviation, σ: 0.10

Count, N: 9
Sum, Σx: 4.438
Mean, μ: 0.498
Variance, σ2: 0.010

1967-1973 (NBA Added 7 teams)
Standard Deviation, σ: 0.14

Count, N: 17
Sum, Σx: 8.1
Mean, μ: 0.470
Variance, σ2: 0.015

1970-1979:
Standard Deviation, σ: 0.07

Count, N: 22
Sum, Σx: 10.8
Mean, μ: 0.494
Variance, σ2: 0.005

1980-1988 (Pre Expansion):
Standard Deviation, σ: 0.10

Count, N: 23
Sum, Σx: 11.5
Mean, μ: 0.500
Variance, σ2: 0.011

1989-1998 (Post Expansion):
Standard Deviation, σ: 0.14

Count, N: 29
Sum, Σx: 14.1
Mean, μ: 0.486
Variance, σ2: 0.017

2004-2021 (Post Expansion)
Standard Deviation, σ: 0.07

Count, N: 30
Sum, Σx: 15.001
Mean, μ: 0.500
Variance, σ2: 0.004

2010-2020 (Also Post Expansion)
Standard Deviation, σ: 0.09

Count, N: 30
Sum, Σx: 14.997
Mean, μ: 0.499
Variance, σ2: 0.007

Initial Thoughts:

The SD of winning percentage clearly increases, in a major way, during Expansion Phases, and the league winning percentage is dragged down significantly, as well.

[ty 4191]

Michael Jordan's Teams went 74-11 (.870) against the 6 Expansion Franchises prior to each team respective team's first time making the playoffs.

Hornets: 18-3
Heat: 14-0
Magic: 12-4
Timberwolves: 13-1
Raptors: 10-2
Grizzlies: 7-1

Citation:
https://howtheyplay.com/team-sports/Why-Michael-Jordan-is-Overrated

See Section: "Jordan Played in a Weak League"

[magicman1978]

the SD says more about the distribution of talent than it does the overall strength of the league. You have to look at how the rosters on these teams were filled:

1. Each existing team was allowed to protect 8 players on it's roster
2. The expansion team was able to draft from the remaining players
3. No existing team can lose more than 1 player
4. Expansion teams can only use 67% of the cap their first year, 80% their second, and then the full cap their third year

This meant that it would take at least 4-5 years before an expansion team could become a competitor if they drafted well (as we saw with the Magic, Heat, and Hornets in the 90s).

This meant there was minimal impact on top teams and the competition faced in the playoffs, especially since rotations were usually cut to 8 at that point anyways.

I think we can all agree that the best teams beat the worst teams. Assessing overall league strength would be a completely separate from assessing how it impacts certain players. For example, if you look to compare Jordan and Magic - would you just simply say Jordan played in a weaker league or would you analyze their competition. Where Jordan never had to face a team as good as the Boston Celtics, but on the other hand he didn't get to coast to the finals multiple times never facing a team with more than 43 wins.

[DQuinn1575]

Michael Jordan's Teams went 74-11 (.870) against the 6 Expansion Franchises prior to each team respective team's first time making the playoffs.

Hornets: 18-3
Heat: 14-0
Magic: 12-4
Timberwolves: 13-1
Raptors: 10-2
Grizzlies: 7-1

Citation:
https://howtheyplay.com/team-sports/Why-Michael-Jordan-is-Overrated

See Section: "Jordan Played in a Weak League"

Ok i had enough of this thread.

[ty 4191]

Jordan's Bulls Versus Expansion Teams, 1989-1998, including Playoffs:

Versus Heat: 39-9
Versus Hornets: 41-10
Versus Timberwolves: 18-1
Versus Magic: 29-15
Versus Raptors: 10-2
Versus Grizzlies: 6-0

143-37 (.794)

[ty 4191]

What percentage of the All Star Level Players in American Professional Basketball were in the NBA (versus the ABA) from 1967-1976?

According to this http://www.apbr.org/forum/viewtopic.php?t=833 10 of the 20 top NBA players in 1977 had been in the ABA in 1976.

To wit: Was the 1967-1977 NBA the weakest league (top to bottom) on record? The league expanded from 12-22 teams in 9 seasons. That is staggering.

I guess, as Socrates said, we must first define out terms.

I might say "league strength", for starters, is (very crude definition here, but bear with me): "The average quality of the average player, multiplied by their playing time, coupled with the spread of winning percentages (Standard Deviation of winning percentage). League parity, in other words."

[ty 4191]

I'm still just pondering which era was toughest and easiest to dominate. And, perhaps, moreso, why?

For individual players, mainly ,since player comparisons and batting around stats on a 1:1 basis is constant around here, yet nobody ever really mentions league strength when comparing player records...

I would say domination for teams is not necessarily indicative of a weak league. But, Dynasties may have a strong correlation with league strength. I honestly don't know anymore.

Thoughts? I'm here to learn. You guys are certainly the scribes and mavens/experts.

Thanks!

[DQuinn1575]

What percentage of the All Star Level Players in American Professional Basketball were in the NBA (versus the ABA) from 1967-1976?

According to this http://www.apbr.org/forum/viewtopic.php?t=833 10 of the 20 top NBA players in 1977 had been in the ABA in 1976.

To wit: Was the 1967-1977 NBA the weakest league (top to bottom) on record? The league expanded from 12-22 teams in 9 seasons. That is staggering.

I guess, as Socrates said, we must first define out terms.

I might say "league strength", for starters, is (very crude definition here, but bear with me): "The average quality of the average player, multiplied by their playing time, coupled with the spread of winning percentages (Standard Deviation of winning percentage). League parity, in other words."

There is a huge difference in the ABA between 1967 and 1976 - the 67 ABA was full of guys who couldnt make the league. There were a lot of guys who were drafted in past years who got cut, and only 1 first round current pick in Mel Daniels.
Couple that with the baby boom generation increasing the talent pool, the demise of the AAU teams due to much higher salaries, players playing longer also due to higher salaries, the integration of high school & college basketball and you have many other factors.

[Cavsfansince84]

1 player exceeded 20 Win Shares from 1979-1988. The average of the top 15 player seasons in Win Shares was 15.

4 players exceeded 20 Win Shares in a season from 1989-1988. The average of the top 15 player seasons was 18.

Wasn't it MJ all 5 times? I don't recall any other player going over 20 win shares in that time(if you meant to type 1998). Having said that, I've long thought that 90's nba was sort of overrated despite having so many big names in it. More so the late 90's as so many guys started having injury issues and the better stars got older.

[LukaTheGOAT]

Kevin Pelton actually took a stable at this topic in this article, although it only includes LeBron and MJ's careers
https://www.espn.com/nba/story/_/id/23456720/is-lebron-james-michael-jordan-greatest-nba-player-all

[penbeast0]

I'm still just pondering which era was toughest and easiest to dominate. And, perhaps, moreso, why?

For individual players, mainly ,since player comparisons and batting around stats on a 1:1 basis is constant around here, yet nobody ever really mentions league strength when comparing player records...

I would say domination for teams is not necessarily indicative of a weak league. But, Dynasties may have a strong correlation with league strength. I honestly don't know anymore.

Thoughts? I'm here to learn. You guys are certainly the scribes and mavens/experts.

Thanks!

Read the top 100 threads if you think no one ever mentions league strength. It's most obvious when talking about Mikan but it's in there quite a bit.

[sansterre]

League strength, or player quality strength?

Obviously the league overall gets worse, as expansion teams artificially bump all the top team records by a few wins.

But do expansions actually drop the average quality of player opponent? ie, does adding four expansion teams between '89 and '90 give Jordan weaker opponents? The answer seems obviously "yes", but how true is that?

After all, it's not like we're grabbing people off the street and making them start. Expansion teams are starting weak starters from other teams and maybe a few bench players: so weaker players go from 20-25 minutes to 30-35 minutes. The "off the street" guys are coming in and playing 5-10 minutes tops. And let's not pretend that the NBA needs to "train more players"; college basketball is churning out tons of guys. There's a reason player quality seems to return to homeostasis only 2-3 years after an expansion.

There are a lot of factors that go into "league player quality". How many teams are in the league? Are there competing leagues? How competitive are the NBA's salaries relative to the rest of the workforce? How famous is the NBA as far as job attractiveness? How well does the NBA (and college basketball scouting generally) identify untapped players for development? What are the working conditions like for the players at the bottom of the league hierarchy; how do they compare with other available jobs in the market? Are there any non-economic factors that would skew the pool from which players can be drawn (like, say, players of one race not being able to play)?

Expansions *always* reduce league player quality. But expansions are, often, not the most powerful factors at work: it is possible (from my research) for the league to expand yet have the average level of quality actually get higher. Not that the expansion made it higher, but that the other forces at play had a bigger positive impact than expansion had a negative impact.

Estimating league player quality from expansion is like trying to estimate whether the Bulls won or lost based on Jordan's box score for the game. It'll be right more often than not, but there are a lot of other (far less intuitive) factors at play.