Throughout xStats you see six categories of batted balls: DB, GB, LD, HD, FB, and PU. These categories are are defined by launch angle, with an emphasis towards separating balls with regards to their single, double, and home run rates. Generally speaking, these batted ball types are displayed as a fraction of the total balls in play (GB%, LD%, etc). It is important to note these numbers are not necessarily predictive, and GB, LD, and HD have very weak Year to Year correlations. Dribble Balls (DB) are very predictive, while the Fly Balls (FB) and Pop Ups (PU) groups are reasonably weak although still somewhat reliable.
Year to Year Correlations | ||||||
---|---|---|---|---|---|---|
Years | DB | GB | LD | HD | FB | PU |
2015-2016 | .729 | .042 | .119 | .165 | .483 | .554 |
2015-2017 | .730 | .199 | .153 | .192 | .435 | .621 |
2016-2017 | .758 | .242 | .122 | .155 | .432 | .574 |
However, these batted ball types were never meant to be used as a predictive tool, but rather as a descriptive one. In particular, they are designed to group players who have created similar contact. When combined with exit velocity, strike out rates, and value hit rates you can narrow down on particular types of batters, which can be useful in many different ways.
These batted ball categories are designed to be a filter, not a predictive tool. Even still, it is good to know the average stats for each of these sit types of batted ball. This morning I updated these figures on the Glossary page, so make sure to check that out.
Moving on from that, you may be curious about the real world stats for individual batters in each of these six categories. Below I have 12 charts, two for each batted ball type, which display the top 30 batters ranked by total Balls In Play and wOBA. Note that the wOBA charts have a minimum of 20 BIP. All of the numbers are from the 2017 season.