Cubs World Series Probability Has Fallen Slightly

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Cubs World Series Probability Has Fallen Slightly

Analysis and Commentary


Well here’s something new.

The Chicago Cubs’ odds of winning the NLCS and advancing to the World Series have dropped. Indeed, by two separate measures (FanGraphs and FiveThirtyEight) the Cubs’ odds have fallen after dropping Game 2 to Clayton Kershaw and the Dodgers.

If you recall, we last checked in on the Cubs’ overall (statistical) chances of reaching the World Series for the first time since 1945, back before Game 1.

At the time, FanGraphs gave the Cubs just a 48.9% chance of reaching the World Series – giving the Dodgers a slight edge, due (primarily) to the healthy reemergence of Clayton Kershaw. Alternatively, FiveThirtyEight was calling the series for the Cubs, placing a huge 64% chance of advancement on them.

But despite the numerical divergence in opinion, both projection systems now seem to agree on one thing: the Cubs’ odds have dropped after splitting the series in Chicago.

Let’s start with FanGraphs. Before the NLCS began, FanGraphs projected the following probability split between the Cubs and the Dodgers.

FanGraphs Odds (Before):

  • Chicago Cubs: 48.9%
  • Los Angeles Dodgers: 51.1%

But after moving to 1-1, headed to Los Angeles, things have changed.

FanGraphs Odds, (After):

  • Chicago Cubs: 47.7% (-1.2%)
  • Los Angeles Dodgers: 52.3% (+1.2%)

So a 1.2% drop/add in both directions and the Dodgers are suddenly favorite by roughly five percentage points. What was previously a standard playoff series coin toss is suddenly a modest Dodger advantage (on paper).

Before the NLCS, FiveThirtyEight had the Cubs as the decided favorite in the series, but things changed pretty quickly and dramatically after a split in Chicago:

FiveThirtyEight Odds, (Before):

  • Chicago Cubs: 64%
  • Los Angeles Dodgers: 36%

FiveThirtyEight Odds, (After):

  • Chicago Cubs: 59% (-5.0%)
  • Los Angeles Dodgers: 41% (+5.0%)

A five percentage point move in each direction is a total shrinking of the Cubs’ advantage by 10 percentage points. From splitting two games.

Which is all a bit wonkers, if you ask me. From what I understand, the probabilities were set before the series began (at whatever they were set at), and then the two most likely scenarios occurred: Jon Lester beat Kenta Maeda at home and Clayton Kershaw won a baseball game. Given how likely both of those scenarios seemed to be at the start of the series, one wouldn’t expect their actuality/realization/occurrence to change the odds so dramatically.

Yes, the Cubs now face a best of five series against the Dodgers, with three of the five games coming in L.A., but Kershaw can start only one of those games (and appear in the bullpen later on); I’m just not convinced the Cubs aren’t still the favorites (or at least that their odds shouldn’t have dropped this much).

At this point, however, there’s nothing we can do but watch, hope, and let the series play out (I’m not sweating, you’re sweating).


Author: Michael Cerami

Michael Cerami is a Writer at Bleacher Nation, and you can find him on Twitter at @Michael_Cerami.