How Good Have the Cubs Been So Far?

One of our readers, Andrew Berman, shared some research he did where he looked into the best starts to the regular season in major league history, specifically referencing the Chicago Cubs and their 20-game tear to open up 2016. Andrew’s research references Bill James’ Pythagorean Winning Percentage, which uses a team's runs scored and runs allowed to estimate their expected win-loss record. Runs scored and allowed are more representative of a team’s underlying performance than wins and losses over a small sample, and so it's no surprise that Pythagorean Winning Percentage has proven more predictive of team's future win-loss records than their actual win-loss records.

As it stands today, the Cubs hold a major league-best 15-5 record. But how does their Pythagorean record stack up against some of baseball’s historically great teams? We went back 75 years and examined each team's first 20 games of the season. Here’s what we found:

The Cubs boast the best Pythagorean Winning Percentage in over 30 years of baseball. Granted, we’re putting stake in only an eighth of a season’s worth of data, but there is some pretty remarkable company shown in the table. Of the bunch, only two teams missed the postseason, while four of the seven who did dress in October found themselves playing for the World Series by season’s end. Let’s see how their run differential compares to some of the great teams of the past.

From top to bottom, the Cubs have done everything well this season, dominating all phases of the game. Their pitching has been spectacular, where they own a league-leading 0.96 WHIP and the league’s third-best ERA at 2.58. As we wrote last week, their defense has been among the best in baseball so far, and their offense has been well above average in its own right. For a bit of perspective on this season, here’s how the run differential leaderboard shapes up through the first 20 games of 2016.

When restricting to only the first 20 games of 2016, the Cubs are well ahead of the rest of the field. While they certainly won’t maintain this torrid pace, their differential of plus-69 runs prorates to 559 over a 162-game season. Give or take 200 runs, and that mark would still easily top the 1998 Yankees’ differential of 309 runs, the greatest difference dating back to 1940. But only time will tell if history was meant to be made in 2016.