By Dan Bernstein– senior columnist

(CBS) Baseball’s playoffs determine the winner of the World Series, not the best team in a given season.

That would already be the 2016 Cubs, who after 162 games over six months have more than earned that designation. They led MLB in total positional player fWAR with 38.7, and their pitchers led in both team ERA at 3.15 and xFIP at 3.74. Their historic defense was good for an Ultimate Zone Rating of 73.7 that outstripped the next-best Giants by 31.1, the biggest differential between the top two since the stat began in 2002.

And that’s why the Cubs won 103 games.

That season is now over, and another one begins Friday night — one governed by the variance inherent in any smaller grouping of games. It’s important to understand that it’s that variance that informs and explains everything about how president of baseball operations Theo Epstein has managed the construction of the Cubs to this point, trying to sustain success over enough time that one or more of their multiple playoff appearances can result in a championship.

This is their second spin of the wheel of baseball fortune. There will be more, but the only one that matters is the one you have right now.

It’s a limited sample in which bad players can be good and good players can be bad, and there’s no way to know any or which or how. When it comes to using numbers to predict likelihoods of postseason outcomes, the smartest analysts now close their laptops and just watch.

If the Cubs win the World Series, it won’t be due to destiny or the force of human will or some Calvinistic preordination. And if they lose, it won’t be the goats or ghosts, curses or voodoo, the weight of history or the failures of human constitution.

It’s just baseball.

Dan Bernstein is a co-host of 670 The Score’s “Boers and Bernstein Show” in afternoon drive. You can follow him on Twitter  @dan_bernstein and read more of his columns here.

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