For most of baseball's history, batting average — hits divided by at-bats — was the dominant measure of offensive performance. The sabermetric revolution of the 1980s–2000s revealed its critical flaw: batting average treats a walk as worth zero, values a single and a home run equally per event, and ignores hit-by-pitches and sacrifice flies. OPS corrects two of these problems simultaneously: OBP captures the ability to reach base (including walks and HBP), and SLG captures power output per at-bat. Their sum provides a single-number offensive rating that, while imperfect, correlates more strongly with run production than batting average.

Why OBP Matters More Than SLG

The two components of OPS are not equally valuable. Research using run expectancy frameworks consistently shows that OBP is worth roughly 1.8× more than SLG in terms of run production. This makes intuitive sense: you cannot score without first reaching base. A player with OBP .400 and SLG .400 (OPS .800) is considerably more valuable than a player with OBP .300 and SLG .500 (OPS .800) despite identical OPS values — the first player reaches base 33% more often. OPS's flaw is treating both components as equally weighted despite their different denominators and run values. wOBA corrects this by using empirically derived run values for each batting event, but OPS remains the more accessible stat because it can be computed mentally from a box score.

wOBA: The More Precise Alternative

wOBA uses the published FanGraphs 2013 coefficients: BB .690, HBP .722, 1B .888, 2B 1.271, 3B 1.616, HR 2.101. This is a dated example, not current-season wOBA. This page assumes intentional walks (IBB) = 0, so all entered BB are unintentional for this estimate. Official wOBA removes IBB from both the walk term and denominator; do not use this estimate unchanged for a line containing IBB. OBP continues to count total walks. FanGraphs.

Using OPS for Player Evaluation

The OPS reference index is an unadjusted fixed 2024-era example: 100 × (OBP/.317 + SLG/.413 − 1). The chart/table reference values are illustrative and do not update by season. No park, league, opponent or season adjustment is applied, so this is not official OPS+ and does not establish cross-era offensive value.