Simplifying Sabermetrics

Week One: OPS (On-Base Plus Slugging)

One of the objectives of Chicks Dig the Long Ball is to educate, not replicate. Most of the baseball chatter you see these days doesn’t end with discussions of batting average and RBIs. Because we recognize that, this year we’ll be hosting a weekly baseball tutorial to assist you in better understanding more of the in-depth analysis you come across throughout the season.

Our getting-started guide can be found at the top menu under “Baseball 101” – this should be your first stop to learn the basics behind the game. There you will find fielding positions, pitch types, common phrases, etc. Each week we’ll build on what we already know, with the goal that over time you’ll be able to decode statisticians and sabermetricians like a pro.

You’ll notice as we get into some of the more complicated statistics that many of these formulas read like measurements of measurements. How many different ways does one person need to assess the same thing? Well, as any statistician will tell you, there are lies, damn lies, and statistics. The more ways we have to measure, or quantify, something, the better picture we can paint when we start to add up all the parts of the whole. Essentially, there’s always more than one way to look at things, and sabermetrics helps us do that with baseball.

I want to start this week with a beginner offensive statistic: On-base plus slugging (OPS). Here is the formula:



However, to comprehend OPS, you must first understand OBP (on-base percentage) and SLG% (slugging percentage). While the OBP measures the frequency a hitter reaches base by way of a hit, walk, sacrifice fly, or being hit by a pitch, SLG% measures how effective a hitter is at reaching base. It is the granddaddy of the power-numbers and is calculated this way:

The idea of “total bases” is a little easier to understand when you break it down this way:

Now, I know for some that looks complicated, but the first rule of thumb in sabermetrics (or any form of statistics, for that matter) is to not let the numbers intimidate you! Slugging percentage essentially assigns a point system to how many times a hitter reaches a particular base or hits a home run.

• A single = 1 point
• A double = 2 points
• A triple = 3 points
• A home run = 4 points

To calculate slugging percentage, you multiply the number of points per hit by how many times a player made that play.

For example:

In 2010, Ryan Howard hit 93 singles, 23 doubles, 5 triples, and 31 home runs over a span of 550 at-bats. Plug his stats into the SLG% equation like so:

According to the calculations, Howard’s 2010 SLG% was .505. He may have finished 13th in the National League (25th overall), but posted the lowest slugging percentage of his career. Compared to previous years, Howard hit more singles in less at-bats (the only exception being in 2006, in which he hit 98 singles in 581 AB), and fewer home runs than usual which caused his percentage to drop. In his MVP year (2006), Howard had a SLG% of .659 (Joey Votto, 2010 NL MVP, had a .600 SLG%, comparatively).

The record for SLG% in a season is .863, set by Barry Bonds in 2001. Babe Ruth had previously held the record (.8 since 1920, his first season with the New York Yankees. Generally speaking, though, anything over .500 is to be revered. Only 103 players have a career .500 or higher SLG% (with at least 3,000 plate appearances) in the history of baseball. Howard is 3rd all-time among active players (trailing only Albert Pujols and Manny Ramirez).

OBP is a stat thrown around frequently enough that it’s almost taken for granted by the casual fan. It’s not fancy, and most people won’t be too impressed that you know it’s meaning, but it has some cool characteristics that are worth looking at more closely.

We now know that slugging percentage measures power. I like to think of OBP as a way to measure a batter’s ability to strategize. There’s more to baseball than the glitz and glamour of a great offensive showcase; sometimes a better approach is simply getting to first base, or moving a runner-up.

Here is the formula for OBP:



This equation takes the sum of batters hits, walks, and hits by pitches, and divides that number by the sum of their at-bats, walks, hits by pitches, and sacrifice fly balls.

For Example:

In 2010, Chase Utley had 117 hits, 63 walks, 18 hits by pitches, 425 at-bats and 5 sacrifice fly balls. Plug his stats into the OBP equation like so:





Based on the work shown above, Chase Utley’s 2010 OBP was .387, which aligns nicely with his career OBP of .380. Ted Williams holds the all-time record with a career OBP of .482, while Albert Pujols leads active players with .426. Only 61 players in MLB history (with a minimum of 3,000 plate appearances) have a career OBP of .400 or higher. Don’t worry about Utley, though – the league average in modern era ball hovers around .340, so he is still well ahead of the curve when it comes to his strategic ball playing.

Now that we have the guts of OPS down, we’re ready to put it all together. Let’s revisit the formula that we started with:



So far we’ve learned that OBP measures a player’s ability to strategize, and SLG% measures how much power he’s packing. Adding the two figures together give us a better understanding of the “complete player.”

To demonstrate, let’s go back to the Ryan Howard example from earlier. In 2010, his SLG% was .505, and his OBP was .353 (152 H, 59 BB, 8 HBP, 550 AB, and 3 SF):



To put it in broad terms, the entire league (all 30 teams) averaged .728 OPS in 2010, and Howard was number 28 on the list of all qualified batters in that season with .858. He is 27th all-time, and 8th of active (qualified) players with a career OPS of .944. Babe Ruth holds the record with a career OPS of 1.1636, and Albert Pujols leads active players with 1.0502.

Now, one may look at Howard’s career numbers and notice that his 2010 OPS was the lowest of his career, similar to his SLG%. Because these two figures go hand in hand, however, this finding is not surprising. It’s easy to shoot from the hip about Howard not playing as well as he has in years past, but in reality all he is doing is becoming more of a well-rounded – “complete” – player. SLG% and OPS are designed to drop when a player’s power numbers are down. This does not necessarily mean someone is playing worse than before, it just means they're playing differently. In some cases, like Howard’s, they’re actually playing better.

Next week, we’ll take OPS one step further and break down OPS+ (adjusted OPS) which takes a few more variables into consideration, but should be a piece of cake now that we’ve begun to lay the foundation! Pin It Now!