Probability in words and numbers, #1
What are the realistic odds a city will land a Major League Soccer team? Probably not even odds. Here’s why.

Journalism often requires that mathematical terms and ideas be explained in simple terms that lacks accuracy. Or the journalist doesn’t realize a mistake has been make. The writer and editor will try to get the message across in a way the reader can understand. But one problem is they won’t realize and catch their mistakes.
This example may seem like nit-picking, but it maters use the right words and numbers. Accuracy matters. A few weeks ago I saw something in an article that immediately caught my eye. I’m not picking on the Nashville Scene, but the reason I run through this example is that it’s an excellent example of using probability in writing.
The Scene put together a good cover story on Nashville’s bid to land a Major League Soccer team, an upgrade from the lower-tier, United Soccer League team that is soon coming to town. A sidebar, “Who Is Nashville’s Competition for an MLS Team,” ran through the cities in the mix and gave the city’s odds of landing a team.
At the beginning of the process, with Sacramento and St. Louis seemingly assured of bids, it looked like Nashville was one of 10 cities fighting for two bids — not great odds. But then St. Louis fell out, along with early favorites Charlotte and San Diego, and all of a sudden, the odds look more like 3 in 7. That’s much more attainable. The sentence is question is the article’s last. Here it is:
At the beginning of the process, with Sacramento and St. Louis seemingly assured of bids, it looked like Nashville was one of 10 cities fighting for two bids — not great odds. But then St. Louis fell out, along with early favorites Charlotte and San Diego, and all of a sudden, the odds look more like 3 in 7. That’s much more attainable.
To recap, Nashville was one of 12 teams in the running for one of four expansion teams. Sacramento appears to have one slot locked up. That leaves three slots for 11 cities. Four of the 11 cities are in serious doubt for various reasons, leaving seven slots for three teams. The entire purpose of the sidebar was to provide information that shows some cities have a better chance than others of landing an expansion team. Again, some teams have a better chance; some teams have a worse chance.
What does that mean for determining odds? Well, each city’s odds probably aren’t 3 in 7. Cities are not chosen at random, out of a hat, using ping pong balls like Powerball picks, choosing straws, etc. Instead, each of the seven cities has somewhere from weak (1 in 100, for example) to strong odds (say, 7 in 10).
The Scene lists cities in order of viability Phoenix is the largest market without a team. Tampa-St. Petersburg has the largest TV market without a team as well as a popular USL team. Cincinnati has a high average attendance. Detroit has a billionaire owner and a large TV market. Raleigh-Durham is a small market. Same with San Antonio. St. Louis, Indianapolis and Charlotte are out of the running. Based on the listed criteria — a soccer-specific stadium, a local ownership group, and a history of fan support for soccer games — Nashville hits all three criteria
So, Nashville could have a 50-percent shot at a team, much higher than 3 in 7. On the other hands, if the market size is a dominant criterion, Nashville’s chances might be as low as, say, 1 in 7, which is far below 3 in 7.
Nashville is a small market but has motivated ownership and government cooperation. Plus, matches at Nashville’s Nissan Stadium, from U.S. national teams to the recent friendly between the Premier League’s Manchester City and Tottenham, have good attendance numbers relative to the market’s population.
But, going along with the Scene, if the seven teams had the same odds (because each slot is chosen at random) Nashville’s odds would be 3/7, or 42.86 percent.
There’s another way to calculate this. Let’s say Nashville has an even chance of losing each of the three rounds. In the first round, Nashville has a 6 in 7 (85.71 percent) of not getting a team. In the second round, the odds rise to 5 in 6 (83.33 percent) because there is one fewer team in the mix. In the third round, the odds increase to 4 in 5 (80.0 percent) because there are two fewer teams in the mix. Multiply the three probabilities the city will not get a team to get Nashville’s probability of not winning one of seven teams: 0.85.71 x 0.183.33 x 0.80 = .5714, or a 57.14 percent chance of not winning one of three teams. Next, subtract 57.14 from 100 percent (100 percent — 57.14 percent) for the odds Nashville will get a team, and you get a 42.86 percent chance Nashville does get one of three expansion teams. Three divided by 7, the odds if cities are chosen at random, is also 42.86 percent.
Few writers and editors are likely to run through the probabilities I’ve laid out. It’s understandable. The point of easy-to-understand numbers is not to bog down the reader in math and create an indecipherable mess. But that doesn’t necessarily make it correct.
