What to Make of Chicago Cubs' Wild Baseball Reference Playoff Odds

[Brian Kelder]

Image courtesy of © Kamil Krzaczynski-Imagn Images

As you may have seen online, the Cubs have the highest odds to win the World Series, according to Baseball Reference. Unexpected? Yes. Does it make sense? Should Cub fans buy in? Let's take a look.

Baseball Reference uses a system they call the Simple Rating System. There are two main components to this: strength of schedule and run differential. The Cubs have just finished the toughest stretch in baseball from strength of schedule. Currently, the run differential for the Cubs is +48, third in the league. When a team has a hard schedule and still produces a high run differential, the Baseball Reference formula will spit out a higher probability.

Another major factor in the Reference formula is the team's record in their past 100 games. This can span seasons, and August and September were not bad months. The Cubs are 54-46 in their past 100 games, an 87-88 win pace. By comparison, the Brewers have been 56-44 (59.8% odds to make the postseason), and the Reds 62-38 (19% odds). 

So basically, the Cubs had a great month against great competition, and their playoff odds are now at 93% by Baseball Reference. This makes sense, given their respective schedules and results. It's just another measure of how good the Cubs have been to start the season.

If you don't believe me, here's a link and then here's the words from that Baseball Reference page:

Quote

MLB playoff odds are based on 1000 simulations of the rest of the season and playoffs. The team's estimated quality is determined by their performance over their last 100 regular season games (even if it spans seasons) and includes a regression to the mean factor. These results are based on standings through 2025-04-29. This page does not update during the postseason.

What should we make of all this? 

Point One: The Cubs have had a great start.
We all know this, and the Reference Odds are a good barometer.

Point Two: It's going to get easier.
In fact, the schedule for the remainder of the season is the easiest in baseball. This has the makings of one of those special seasons. (Here's a link to the schedule strength so far.)

Point Three: The NL Central is not respected.
Part of these odds are the higher chance that the Cubs win their division. The Brewers seem to have finally been affected by their talent drips from the past few years. The Reds don't have a stellar recent history, and we won't mention the Cardinals or Pirates. The Cubs are in the drivers' seat.

Now, this is a statistics-based measurement, and the past two months of May were not happy for the Cubs. In 2023, the Cubs collapsed to a 10-18 record, and in 2024 they were 12-16. With divisional play heating up, the Cubs can ill afford another May cold stretch.

And it is still a possibility. After Justin Steele's elbow reconstruction, the rotation is being held together by duct tape and elbow grease. If Colin Rea regresses to the mean, Matthew Boyd has his seemingly inevitable injury, or Ben Brown continues to have noncompetitive games, the pitching will not hold up, no matter who the opponent is. These odds don't speak to any of that, because unlike other Playoff Odds models (Baseball Prospectus's, fueled by PECOTA, or FanGraphs's, fueled by ZiPS and STEAMER), Baseball Reference's don't use individual player projections. They're solely rooted in the indices of recent past performance and schedule strength that we've already talked about. That makes them fundamentally different, and importantly so. Both of the projections-based systems are lower on the Cubs than this.

But that's a hypothetical, negative outlook, and one that doesn't serve the thesis statement. This is a month for optimism. The Cubs are World Series favorites! It's a month to be celebrated, not one to worry about something that hasn't happened yet. And even then, Cade Horton  is increasingly looking like an option sooner rather than later.

Sit back, enjoy the ride, and know that at least statistically, the Cubs measure up with any team in baseball. 

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