Unlike statistics like OPS, wOBA attempts to assign the proper value for each type of hitting event.
It was created by Tom Tango and his coauthors for The Book: Playing the Percentages in Baseball.
[3] In 2008, sabermetrics website FanGraphs began listing the current and historical wOBA for all players in Major League Baseball.
[4] It forms the basis of the offensive component of their wins above replacement (WAR) metric.
Sites such as The Hardball Times have studied wOBA and found it to perform comparably to or better than other similar tools (OPS, RC, etc.)
[5][6] The Book uses wOBA in numerous studies to test the validity of many aspects of baseball conventional wisdom.
The weighting is based on the increase in expected runs for the event type as compared to an out.
Because the coefficients are derived from expected run value, we can use wOBA to estimate a few more things about a player's production and baseball as a whole.
When using the formula (shown below), the numerator side on its own will give us an estimate of how many runs a player is worth to his team.
[10] Balls hit hard (i.e. with a high exit velocity) in the sweet spot produce higher wOBA.
where: The following table serves as an aggregate summary of various wOBA scales available online.