Sabermetrics Library

Description:

The one sabermetric statistic that has grabbed a toe-hold on the wider public conscience, On-base Plus Slugging (OPS) is exactly what it sounds like: the sum of a player’s on-base percentage and their slugging percentage.  While OBP is actually more valuable than SLG%, OPS has value as a metric because it is the only publicly accepted statistic that accounts for all the different aspects of offense: contact, patience, and and power.

On-base Plus Slugging Plus (OPS+), on the other hand, has not gained as much widespread acceptance but in many ways is the superior metric.  A one-hundred OPS+ is league average and each point up or down is one percentage  point above or below league average.  In other words, if a player had a 90 OPS+ last season, that means their OPS was 10% below league average.  Also, an important point to remember is that OPS+ adjusts for league and park effects, making it possible to compare players from different years and on different teams using OPS+.

Context:

2009 OPS Numbers

2009 OPS+ Numbers

Things to Remember:

• If you’re looking to evaluate a player’s offense, OPS is a better metric to use than batting average, but should always be used in conjunction with other statistics as well.  It’s also a good gateway stat to get people moving from beyond the traditional statistics.
• If you have the choice, use wOBA instead of OPS.  OPS weighs both OBP and SLG% the same, while wOBA accounts for the fact that OBP is actually more valuable for scoring runs.
• Since it provides context and adjusts for park and league effects, OPS+ is better to use than straight OPS, especially if you’re comparing players.

Links for Further Reading:

Intro to OPS+ – Big League Stew

Baseball Basics: OPS – Baseball Prospectus

On-Base Plus Slugging – Wikipedia