What does a city’s baseball team tell us about the size of its airport?

Listen to this podcast episode HERE or on your preferred podcast platform.

We all develop specific subconscious associations based on our experiences. Most are simple and reasonable, like associating the smell of freshly cut grass with the sport you most enjoy playing on it.

But others are more complex and harder to discover. Two years ago, I realized I had developed a weird one. Flying into the Colorado Springs airport, I perceived the size and logistics of the terminal in relation to the fact that the city had a Triple-A baseball team.

This led me to conduct a simple study.

The Premise: A the size of a city’s airport correlates to the level of professional baseball team that plays there.

Now, that premise is based on the fact that the level of baseball team in a city is a function of the market’s size–as is the business of the airport. So, as Paul astutely points out in the episode, this is an instance of correlation being independent of any causation.

Nevertheless, is it accurate to group the size of city’s airports into tiers like professional baseball teams? Let’s find out.

The Methodology: In order to find out the relation between the size of an airport and the level of baseball team, we have to quantify both categories. Forbes posted a list of the top 100 US airports by passenger travel in 2017. We’ll use these numbers to quantify the size of airports.

Major League Baseball affiliated teams are grouped into a few different, somewhat confusing, levels. For simplicity we’ll use rookie leagues/short-season Single-A as tier 1, Single-A as tier 2, Double-A 3, Triple-A 4, and MLB 5. Each team earns a “baseball score” for its city, to be compared against the passenger travel.

We’ll use the quotient of these two quantities to analyze our data. Dividing passenger travel by baseball score, we get a passenger-to-baseball ratio. We’ll call it the PTB.

If my premise, at its bare bones, were correct, all the PTB’s would come out to about the same number. A Major League city, scoring 5, would have roughly the same number of passengers as any other Major League city; those cities’ airports would be roughly the same size. At the outset of this experiment, though, we know that will not be true. New York, with its 8 million people is going to have a far busier airport, and therefore a far higher PTB, than Cincinnati, with its 300,000 people.

So, in order to cover our bases, we’ll include every MLB-affiliated team within 30 miles of the city. Therefore, New York’s baseball score will reflect both its MLB teams and an assortment of Minor League teams that play nearby.

But if we’re doing that, we also need to include every airport that serves the city. New York, for instance, has three (JFK, LaGuardia, and Newark). Washington, D.C. has two because we’ll save BWI for Baltimore exclusively. And there are several other cities that have multiple airports in Forbes’ top 100 list.

That will make the ratios slightly more reflective of the actual air travel and baseball that occurs in the metropolitan area.

Gathering all the passenger traffic and baseball scores for each city, we ran the numbers.

The Results:

This graph plots PTB’s for each city.

What you see is that most Major League cities (left side of the horizontal axis) have much higher PTB’s than Minor League cities.

Why is this? Well, on our baseball score scale, we’re giving MLB teams a 5 and Triple-A teams a 4. But really, a Triple-A market is not just 20% smaller than an MLB market. If baseball team level is a function of the size of the city, let’s consider what that baseball team actually tells us about the market size.

So, we found some attendance numbers.

BaseballPilgrimages.com listed attendance figures for all the different levels of baseball in 2017. Adding up all the numbers for each level, we got figures in the millions, naturally. So we divided each attendance figure by the lowest, which conveniently belonged to the short-season Single-A and advanced rookie leagues, so that the lowest baseball score would still be 1. Single-A came out to 1.2, meaning Single-A attendance was 1.2 times that of the lower leagues. Double-A 1.8, Triple-A 2.8, and MLB 12.3.

So now, MLB’s baseball score more accurately reflects its markets and most likely the traffic that would give its cities’ airports their size.

Running the numbers again, we got a much more compact spread.

Again, if the premise were correct, the graph would be a relatively straight line. You see that a lot of PTB’s fall in the 1-3 range.

This attendance-adjusted PTB highlights a few cities nicely, though. Namely, Las Vegas, Charlotte, Salt Lake City, and Portland.

The former three cities are all Triple-A cities with a lot of air traffic. Charlotte and Salt Lake are hubs for American and Delta, respectively, which means they have the air traffic of a large city divided by the baseball score of just a Triple-A city (4 times smaller than an MLB city). Las Vegas, while not technically a hub for anyone I’m aware of, has a lot of transient traffic for obvious reasons.

Portland, on the other hand, is a true outlier. While it passed almost 9.5 million passengers in 2017, it only hosts a short-season Single-A baseball team–in Hillsboro no less, not even in Portland proper.

The truest outlier though does not even appear on the graph because dividing by zero is mathematically undefinable. Orlando.

Orlando is the 11th-busiest city by air traffic, yet there is no professional baseball team within 30 miles. The Florida Fire Frogs used to play in nearby Kissimmee, but have since moved to North Port along with the Atlanta Braves’ Spring Training.

On a broader scope, there are a few interesting trends to note. The busiest seven cities all host one or more MLB teams. Las Vegas, at eight, has the busiest airport without one. Orlando, at 11, is far and away the busiest city without any baseball team. The next is Honolulu at 27, which has a much better excuse for lacking the sport at a professional level.

The least-busy MLB city is Milwaukee, ranked 51. Above Milwaukee, but rounding out the four least-busy MLB cities are Cincinnati, Pittsburgh, and Cleveland, which are all rust-belt cities without airline hubs. They have very low PTB’s–around 0.3.

One spot ahead of Pittsburgh in air traffic is Ft. Myers, Florida, which hosts the Mighty Mussels, a Single-A team. Ft. Myers, by the way, with its relative busyness, has a high PTB (3.7) among Single-A cities. Even higher than it, though, is San Jose, California (5.2)

The Conclusion: Reasons why a city’s airport is or isn’t busy are nuanced. Even more so are the reasons why a city does or doesn’t have a certain baseball team. For instance, Colorado Springs’ Triple-A team moved to San Antonio after 2018. Now, Colorado Springs has the Brewers’ rookie league affiliate. That move boosted its PTB from 0.3 to a more on-par 0.8.

So the premise is, of course, imperfect. However, when accounting for attendance, there is an obvious relation between the size of a city’s airport and the level of its team for reasons that extend not much further than the fact that bigger cities have bigger markets and higher levels of sports.

MLB cities with extremely low PTB’s are the rust belt locales mentioned above. These cities were  among the most populous in America back when rail travel ruled the continent and the baseball clubs were established. The teams have rich history even though the cities no longer stand with the prominence they once did. Given their proximity to larger northeast cities, it’s understandable that they have relatively smaller airports.

Conversely, we see in the cities with the highest PTB’s examples of the country’s westward migration. These Sun Belt cities, and Portland, highlight future expansion opportunities for Major League Baseball.