Weird numbers: More fans at The K through the years, the less the Royals win

To give the Kansas City Royals the best chance of winning tonight’s American League Wild Card Game, fans should consider staying home.

At least that’s what 29 years of data suggests.

“In general, the more people in the stands, the less the Royals win,” said Ryan Sleeper, who found that there’s a loose correlation between the Royal’s winning percentage and the number of fans in attendance at Kauffman Stadium.

Sleeper is quick to point out that correlation does not indicate causation.

For example, highly attended games are typically against popular, more competitive teams who have many of their own fans in attendance, he said. For example, St. Louis.

Sleeper, director of data visualization and analysis at the consulting firm Evolytics in Parkville, grew up as Royals fan and has been to a few games that drew large crowds, but had disappointing endings.

“I always had this hunch that we don’t perform quite as well when it’s a full stadium,” he said.

The last straw was the Royals being crushed by the Detroit Tigers 10-1 on Sept. 19 in front of a full Kauffman Stadium.

With the Royals hosting tonight’s American League Wild Card game, he just had to find out what the data showed.

“I wanted to see how we might fare based on the assumption that it’s going to be completely full tonight,” he said.

Looking at the 2,311 home games from 1986 through this season, the data shows that when there’s a crowd of less than 10,000 people in the stands, the Royals have an above average winning percentage, he said.

But from that point, the winning percentage decreases as the number of fans grow — all the way up to 41,000 in attendance.

Don’t fret, because the data shows there is some hope.

“When you get to the last attendance level of 41,000 or more — that has happened nine times since 1985 — we have won seven of those games,” Sleeper said.

But just as quick as the data gives a glimmer of hope, it takes it away ... five of the seven wins came from the 1986 to 1990 Royals.

Also, there’s the caveat that the current generation of Royals players — those who have played during the past five years — has never played in front of more than 41,000 fans at home. (When Kauffman Stadium was renovated, seating capacity to 37,903.)

The current generation has played in front of 40,000-plus fans five times, winning two of those games, he said.

Sleeper created a data visualization of the Royals Winning Percentage versus Average Attendance which can be found by clicking here.

He also created a visualization looking at the 4,627 Royals games since the Royals were in the playoffs.

But despite the data shows, he doesn’t fans will stay away.

“The bottom line is: I don’t think I would miss this game for anything,” said Sleeper, who has tickets for tonight’s game.

“I don’t think it matters to many Royals fans.”

This story was originally published September 30, 2014 at 12:15 PM with the headline "Weird numbers: More fans at The K through the years, the less the Royals win."