How to evaluate a team, sabermetrically

The Twins are 4-0! They’re going to win the World Series! The Rangers are 1-3! Here comes a 100-loss season! All these over-exaggerations are just part of the opening week of the Major League Baseball season.

Some hot or cold April starts can turn into something more. The Phillies started the 2016 season 24-17, leading some people to believe that a breakout was in the works. Despite this, the team regressed pretty heavily, going 47-74 in their final 121 games and finishing with a 71-91 record, about indicative of the talent they had on the team.

Before we start to consider the Twins contenders—although, nobody should be doing this because it’s just been four games—it’s important to have an understanding of the best way to evaluate a team beyond their win-loss record. Yes, record is still the No. 1 indicator of a team’s performance. After all, it’s what gets them into the postseason and determines their seeding. But, there are other ways to understand the strength of a team, which in turn helps us figure out who has the best chance to win the pennant and the World Series.

Run Differential

The easiest way to evaluate a team is through their run differential (RD). Run differential is the amount of runs a team has allowed subtracted from the amount that they have scored. It’s simple to understand, and it can go a long way to see if a team’s performance is true to their talent.

In theory, under the same conditions, if Team A beats Team B 6-5 and Team C beats Team B 10-0, it’s easy to see that Team C is likely a stronger team than Team A. Team A may have gotten a lucky bounce somewhere, in the form of an error, bases-loaded walk or a home run on a bad pitch, that got them their win. Team C, though, was clearly superior to Team B. They hit the baseball well and scored a lot of runs, in addition to keeping them from scoring. Team C had a dominant game. Team A and Team C both are 1-0 under this scenario, but Team A’s RD is +1 while Team C’s RD is +10.

If this doesn’t convince you enough, consider this. The 2016 Cubs, the first 103-win team in Major League Baseball since the 2009 Yankees, went just 22-23 in one-run games last season. That ranked 17th in the Major Leagues. But, they went 42-13 in games decided by more than five runs, a testament to the Cubs’ dominance.

Overall, the Cubs’ RD was +252. For a time, there was a chance that they could have broken the record for best season RD. That was 68 runs better than the team that finished in 2nd, the Boston Red Sox. Here are the Top 10 in RD from 2016:

Interestingly enough, the best teams on this list all made the playoffs. That isn’t a surprise because wins directly correlate to positives in the RD column. A team cannot win a game and allow their RD to go down.

What is a surprise here, though, is that the Rangers, who tied for 2nd in the Majors with 95 wins last season, are not listed. In fact, you’d have to go all the way down to 14th to find Texas, who were behind all four Wild Cards and four non-playoff teams on the rankings. How did they go 95-67? The Rangers went 36-11 in one-run games. No other team in the Major Leagues had more than 30 of such wins. That, in fact, was the Mariners, who posted a 30-30 record in those opportunities, which is considered “expected.” Texas also went 18-24 in blowouts.

Am I surprised, then, that the Blue Jays (who ranked 5th in RD) swept them in the ALDS? No. The Blue Jays were a better team, hands-down.

Run Differential tells us the strength of teams, but it doesn’t always correlate to World Series success. Here are the past 15 World Series-winning teams and where their run differential ranked among their league counterparts:

Nine out of the fifteen (a solid 60%) of the past World Series winners ranked in the Top-5 of baseball in Run Differential, and one-third of the past 15 ranked 1st in the league in run differential. To compare, if you finish in the top 5 in the league in RD, it’s equivalent to getting a No. 1 seed in the NCAA Basketball Tournament. No. 1 seeds have won 61% of all National Championships since the tournament expanded to 64 teams in 1985.

So, while it’s a good position to be in, the best teams can always be knocked off, just like in March Madness. The 2006 Cardinals, finishing 15th in RD, would be like a No. 3 or No. 4 winning the tournament, which has happened just five times.

Pythagorean Record

Run differential tells us a lot, but it does not tell us everything. These next two metrics, pythagorean record and simple rating system, tell us more about the team.

Pythagorean record attempts to figure out what a team’s record should be using their run differential. As you’d expect, the best teams in run differential also have the best pythagorean records. But, the question pythagorean record tries to answer is a bit different. For instance, if the Rangers were that bad in RD last year, then how many games should they have won under normal circumstances? That’s what pythagorean record will tell you.

And, not shockingly, the Rangers had just an 82-80 pythagorean record. This means that their overall record was 13 wins better than their pythagorean, or “expected,” record. The Cubs, on the other hand, were actually four wins worse than their pythagorean record, if you can believe that. Under normal circumstances, the Cubs would have been a 107-win team.

If you want to see how good your team should be, pythagorean record is the metric for you. It’s too early this season to know what teams are outperforming their records, but if the 2016 Phillies prove any indication, it will not be long until we understand their true talents. They were 15-10 after the league’s first month, but according to their pythagorean record, they should have been 10-15. To compare, the 2016 Reds actually were 10-15 after the first month, and them and the Phillies finished within five wins of one another. Once April is over, we will have a much somewhat clearer picture of which teams are actually good.

Simple Rating System

The last easy way to evaluate a team sabermetrically is by using Baseball-Reference’s Simple Rating System (SRS).

Also derived from run differential, SRS tries to simplify (hence it being called the simple rating system) each team’s performance into one number. SRS rates a team on the number of runs they are, on a per game basis, above or below the average Major League team. It is adjusted for strength of schedule.

It’s important to include those adjustments because each team does not play the same schedule, and we have been comparing them as if they did. Playing a tougher schedule could damper a team’s run differential and vice versa.

The Rangers fare better here, but they still aren’t great, at 12th with just 0.2 runs above average per game. The Cubs, again, are 1st at 1.3 runs above average per game, but are no longer in a league of their own. The Red Sox tie them in SRS, also posting a 1.3 mark, due to their tough AL East schedule, which is 0.3 runs better per game than the Cubs’ NL Central schedule.

So, this season, before you jump to outrageous conclusions, check run differential, pythagorean record, or the simple rating system to see how strong your team really is.