How Much Parity is in Each Major Pro Sports Championship?

The Super Bowl, NBA Finals, World Series, and Stanley Cup Finals have been seminal celebrations on the North American sports calendar every year for decades. The balance of power has ebbed and flowed, dynasties have risen and fallen, and new names have cycled up to the top before stepping back for another to occupy the space. Some organizations have reached the pinnacle more than others, but no crown is permanent.

All champions decompose eventually. It’s not unusual for a team to ride a high for between three and five years, appear in multiple championship games or series, snatch a few rings along the way, then fall back down into the bucket with the rest of the crabs. Coaches retire, contracts expire, and draft picks don’t quite hit as they used to – change is a fact of life, and sports are not immune.

How often do these cycles last, though? How often do teams return back to their league’s ultimate event within a short window of time, a period small enough for the same core to remain relatively intact? How consistently does this rotation of contenders occur within each of the four major North American professional sports, and what can learn from this information?

Let’s take a look back at the pasts of the NFL, NBA, MLB, and NHL to get a better understanding of their cycle lengths, how they’ve changed throughout time, and what it might tell us about what we can expect in the future.

How Does This Work?

I looked back at every single Super Bowl, NBA Finals, World Series, and Stanley Cup Finals ever played. I recorded how often teams have reappeared in their championship game or series within windows of three and five years, then cross-referenced them against other leagues to see whose forefront has had more frequent fresh faces.

I chose to use cutoffs of three and five seasons because they both capture the standard lengths of players contracts in all four of the leagues. Team rosters usually don’t look wildly different from one season to the next, but if you were to compare rosters from three campaigns apart, you’d notice a much wider variation. It grows even more after five years. But for the best teams that are making runs at rings, there is always a core that remains rooted for the duration of the peak. Age, free agency, trades, and general attrition will inevitably wear that down, and after more than a half-decade, most sports teams only have a handful of hangers-on from the older era.

For the NFL, NBA, and MLB, I took into account every Super Bowl, NBA Finals, and World Series ever played. I had to treat the NHL and the Stanley Cup Finals a bit differently, though: prior to the expansion of 1967, the league spent decades with only six teams. This does not foster many cycles. The data from 1968 to the present day is much more representative of the modern NHL, and so it is what I utilized.

This is what I learned about each of the four major professional sports leagues.

NFL

Number of Super Bowls: 57

Number of Super Bowl participants: 114

Percent of Super Bowl returners (3 years): 36.84% (42/114)

Percent of Super Bowl returners (5 years): 44.74% (51/114)

Super Bowls with at least one returner (3 years): 63.16% (36/57)

Super Bowls with at least one returner (5 years): 71.93% (41/57)

Participants in the last three Super Bowls: Kansas City Chiefs, Philadelphia Eagles, Los Angeles Rams, Cincinnati Bengals, Tampa Bay Buccaneers

Last Super Bowl with no returners (5 years): 2019 (Kansas City Chiefs beat San Francisco 49ers)

No league has had a greater turnover in its championship contest than the NFL. The league has the lowest percentage in each of the four categories I evaluated, a sign that if the NFL’s goal was parity, then it has done a fantastic job of achieving it.

Like any league, the NFL has had its dynasties, but they don’t seem to last for as long. In the 1970s, the Cowboys, Dolphins, Vikings, and Steelers were regularly in the Super Bowl, combining for 15 total appearances among them during the decade. By the 1980s, all four of them had been entirely replaced at the top of the league, and the NFL has not had that many teams have that strong of a hold on the Super Bowl for that long again.

On only six occasions has the Super Bowl included two teams that both played in one of the prior three Super Bowls (1978, 1983, 1984, 1989, 1993, 2014). Three times in NFL history, there has been no overlap from the last three Super Bowls for at least three seasons in a row (1980-1982, 1999-2002, 2011-2013). Roughly one-third of all Super Bowl contestants have gone back to the big game within the next three seasons, which is decisively less than any of the other four major leagues.

It seems as though the window of opportunity for new teams to replace the old guard is greater in the NFL than elsewhere, likely in part due to the high variation that comes with regular seasons that last a fraction of the time compared to most other leagues and a single-elimination playoff format. The physical strain the sport puts on its athletes also leads to shorter careers, which means more player turnover and championship churn. It’s with good reason that the National Football League is like this.

When put in this perspective, it makes some of the NFL’s greatest dynasties that much more impressive. That the Patriots reached eight Super Bowls between 2001 and 2018 is remarkable, and how they did it – with an all-time coach and all-time quarterback who both delivered the same high-level performances for the same organization for decades – illustrates just how perfect everything has to go for an NFL team to find that level of consistent success. To build something that goes on beyond a few years is unbelievably difficult. Conversely, this means that rising up the ranks quickly is more achievable than in most other leagues, which is how you got a period like from 1999 through 2013 when nine of 15 Super Bowls had zero three-year returners.

NBA

Number of NBA Finals: 77

Number of NBA Finals participants: 154

Percent of NBA Finals returners (3 years): 56.49% (87/154)

Percent of NBA Finals returners (5 years): 62.99% (97/154)

NBA Finals with at least one returner (3 years): 77.92% (60/77)

NBA Finals with at least one returner (5 years): 84.42% (65/77)

Participants in the last three NBA Finals: Denver Nuggets, Miami Heat, Golden State Warriors, Boston Celtics, Milwaukee Bucks, Phoenix Suns

Last NBA Finals with no returners (5 years): 2021 (Milwaukee Bucks beat Phoenix Suns)

The NBA has the highest frequency of returners to its championship series. More than 50 percent of every NBA Finals participant ever had already been in the Finals in one of the previous three seasons, and nearly 63 percent of every NBA Finals contestant had played in the event at some point in the last five editions. None of the other major North American pro leagues have had teams remain at the top to that degree.

You can’t discuss success in the NBA without broaching the Boston Celtics and Los Angeles Lakers. The two franchises are bitter rivals, which doesn’t make much sense at face value – why would teams on the polar ends of the United States hate each other so much? But if you understand how dominant these two organizations have been throughout the league’s history, then it makes more sense. With 54 appearances in the league’s title-deciding series between them, the Celtics and Lakers alone make up more than one-third of all NBA Finals outfits. Their grip on their respective conferences has led to the NBA experiencing much less turnover in its Finals than other leagues.

In general, the teams that place themselves atop the Association don’t give up that spot so easily. NBA players don’t take the same kind of beatings as NFL players do, so their careers and primes can last longer. Basketball is also the most individual-oriented sport played by the four major leagues, so one or two NBA players can have a much greater impact on a game or the overall quality of a team than in other North American leagues. The nature of a four-round playoff, all including a best-of-seven series, throws a lot more data points in the mix and lowers the likelihood of upsets, flukes, and other anomalies that are more expected in leagues like the NFL and NHL.

There have been 28 instances of both NBA Finals teams being returners from the last three seasons, and the championship series has been an exact rematch from the year before on 16 different occasions. Almost 78 percent of all NBA Finals have had at least one returner from the last three years and nearly 85 percent have had at least one returner from the previous five seasons.

Basically, there’s a pretty good chance that the 2024 NBA Finals will include at least one of the Denver Nuggets, Miami Heat, Golden State Warriors, Milwaukee Bucks, or Phoenix Suns. It’s also more probable in the NBA than elsewhere that both participants will come from that list. Keep that in mind when you place futures bets or submit entries to NBA pools.

MLB

Number of World Series: 118

Number of World Series participants: 236

Percent of World Series returners (3 years): 47.46% (112/236)

Percent of Word Series returners (5 years): 54.24% (128/236)

World Series with at least one returner (3 years): 77.97% (92/118)

World Series with at least one returner (5 years): 93.90% (99/118)

Participants in the last three World Series: Houston Astros, Philadelphia Phillies, Atlanta Braves, Los Angeles Dodgers, Tampa Bay Rays

Last World Series with no returners (5 years): 2017 (Houston Astros beat Los Angeles Dodgers)

It’s probable that the 2023 World Series will include at least one returning team that participated in any of the previous five iterations. That’s been the case in 93.9 percent of all Fall Classics since the first one in 1903. Congratulations to the Houston Astros, Philadelphia Phillies, Atlanta Braves, Los Angeles Dodgers, Tampa Bay Rays, Washington Nationals, and Boston Red Sox – at least one of you is in good shape to play in the upcoming World Series!

No other league reviewed in this article has had that many championships with at least one returner in a five-year span. MLB narrowly outdoes the NBA in the same category with a shortened length of three years. However, Major League Baseball’s overall returning rates are lower than the NBA’s. This means that while any given World Series is more likely to include a team from a recent one, it’s more likely that both competitors fit that criterion in the NBA Finals than in the Fall Classic. It’s also important to consider that there have been 118 World Series to just 77 NBA Finals, how differently both leagues structure their postseasons, and the massive changes each entity has endured since their earliest eras.

After the New York Yankees beat the Los Angeles Dodgers in the 1978 World Series for the second season in a row, an abrupt shift occurred in Major League Baseball. In the 43 Fall Classics since, 31 teams have returned to the World Series within three years of being there, a large drop-off from the 50 teams that did it in the 43 that preceded from 1936 through 1978.

Still, MLB has the longest-active fresh championship matchup drought, last pitting two fresh faces against one another in 2017. That and the 2016 World Series are the only ones to not include at least one returner from the previous three years dating back to 2011, a frequency that even the NBA has beat. In baseball, the likelihood that the ultimate series will include a familiar face is high, but it’s not common for both participants to have been there within the last three tries. It hasn’t happened a single time since the turn of the millennium and occurred just once since 1982: the 1999 World Series between the Yankees and Braves.

What all of this tells me is that it’s normal for one MLB team to grow to rule the roost, making regular World Series runs for a period of time while its challengers often rotate. This contrasts with a league like the NBA, where it’s more standard for two or three elite teams to duke it out amongst themselves for a few years before a new crop takes their place.

NHL

Number of Stanley Cup Finals: 56

Number of Stanley Cup Finals participants: 112

Percent of Stanley Cup Finals returners (3 years): 41.96% (47/112)

Percent of Stanley Cup Finals returners (5 years): 50.00% (56/112)

Stanley Cup Finals with at least one returner (3 years): 66.07% (37/56)

Stanley Cup Finals with at least one returner (5 years): 78.57% (44/56)

Participants in the last three Stanley Cup Finals: Vegas Golden Knights, Florida Panthers, Colorado Avalanche, Tampa Bay Lightning, Montreal Canadiens

Last Stanley Cup Finals with no returners (5 years): 2023 (Vegas Golden Knights beat Florida Panthers)

The NHL has fostered plenty of healthy competition since its first modern expansion in 1967, and as the league has grown, that has bore itself even more obvious. The league has had a higher percentage of returners in every category as compared to the NFL while ranking well below the NBA and MLB in each factor. But what stands out about the National Hockey League is how infrequent quick returners have become in more recent times.

Since the Edmonton Oilers released their stranglehold on the NHL following their 1990 Stanley Cup championship, the league has experienced 17 Stanley Cup Finals without a returner from the last three years. In the same time frame, there have been only 12 Super Bowls, nine NBA Finals, and eight World Series without a returner from the previous three editions. Dating back to 1991, the NHL has also had a three-year returner rate of only 26.6 percent to the NFL’s 34.4 percent, MLB’s 37.5 percent, and the NBA’s 48.5 percent.

When you open the window a bit wider, though, the NHL doesn’t quite show the same level of parity. Expanding the limit for returners to five years adds seven more to the NHL’s list, which is more than NBA’s six, NFL’s five (and only three since 1995), and MLB’s two. This might mean that while it’s more common for the Stanley Cup challengers to swap out than in other leagues, the NHL’s best is more likely to linger for a longer time and rise back up to prominence than teams aiming to build dynasties in the other leagues.

Still, the NHL seems to have surpassed the NFL in parity in the last three decades or so, at least in regard to cycling through championship competitors, and it left the NBA and MLB behind long ago. It turns out that when your sport is entirely based on a piece of rubber bouncing around on a thick sheet of ice, results can vary. Instituting the most grueling playoffs of the four major North American pro sports leagues can have the same effect.