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Introducing FanGraphs Stats: Offense and Defense
Posted By Dave Cameron On September 19, 2013 @ 2:16 pm In Daily Graphings,Featured | 89 Comments
FanGraphs has a lot of metrics, ranging from the standard counting numbers that have filled baseball cards for decades to more complicated calculations and formulas. Odds are pretty good that if there’s something you want to know about a particular Major League player, we probably have a metric for it. However, up until today, we’ve lacked one number that answered two of the most basic questions that people ask: Who has been the best offensive player in the game, and who has been the best defensive player in the game?
You could get at those questions with the numbers we had, using a combination of metrics found on the site, but there wasn’t just a single number that simply answered those two questions. And, unfortunately, the lack of an available sum of offense or defensive value led to people occasionally substituting in a number that didn’t actually answer the question they were trying to answer. This was our fault, not theirs, but as of an hour ago, this has been rectified with the introduction of two new numbers here on FanGraphs.
On the dashboard and in the value section, you will find two columns simply labeled Off and Def, which stand for Offense and Defense. These numbers are the total runs above or below average based on offensive contributions (both batting and baserunning) or defensive contributions (fielding and position). While both numbers are simply the addition of two metrics previously available, this gives everyone the ability to now simply quote, in runs, how far a player was from the league average in either creating or saving runs.
For instance, here are the 2013 leaders in offensive runs, combining their batting and baserunning totals:
I’m going to skip over the top two names on the list because we all know how this will go if I open that can of worms. But look down at #4 and #5; by combining batting and baserunning, we can plainly see that Andrew McCutchen has been the best offensive player in the National League this year. Without even considering the run prevention side of things, McCutchen has a slight lead over Paul Goldschmidt. This helps make the case for McCutchen as MVP even for people who are skeptical of defensive metrics and prefer to base their decision almost entirely on what a player did in the parts of the game that are easier to measure.
Now, for the same leaderboard, only focusing on the defensive side.
This is where the upgrade was needed the most. Prior to this rollout, we listed “Fld” as our primary defensive rating on both the dashboard and the fielding section, which solely rated players relative to average at their specific positions, but that treats all positions as if they are equal in value, which is clearly not true. Pretty much every shortstop is a better defender than every first baseman, even the ones with negative ratings at SS compared to the guys with positive ratings at 1B. But, with the Fld metric, this wasn’t always obvious, and it led to people using a metric that rates players at their position as if that was their standing in the league overall.
By adding the positional adjustment into the fielding rating to create Defense, we’re now presenting a much better view of who the best defenders actually are. Catchers get a big boost here as well, as they have the largest positional adjustment of any spot on the field, and this better recognizes their contributions, even if they aren’t necessarily rated dramatically higher than other catchers. Just being a catcher has a lot of value, and this helps display that value more correctly.
There are some other ancillary benefits to displaying things in this matter as well. Since these are counting stats, playing time is explicitly included, so a player who has posted a .400 wOBA over 150 games will grade out better than a player who had the same .400 wOBA in only 100 games. Rate stats can be very useful, but when counting total value, you also want to give players credit for staying in the line-up every day. Now, instead of having to just cite wOBA or wRC+ and then adjust for both playing time and baserunning value, those are already baked into the Offense column.
This also helps level the playing field for guys who shift between positions. Utility players who spend parts of their season at multiple positions, or even regulars who bounce around between spots like Ben Zobrist, do not have their defensive performance easily described by a single UZR rating. If a guy plays five positions and has a +5 UZR, you don’t really know what that +5 is relative to. Now, with the fielding component added in, you know that the baseline is an average defender across all positions.
And, finally, if you don’t want to try to spend time talking about what a replacement level player is, this gives you an easy way to simply compare players relative to league average, a baseline that is easily understood without any explanation. Replacement level is an important concept, but there are times it is not necessary to add in those extra runs, and a comparison to average will do just fine. For those times, these metrics now make those citations easier.
You will find Off and Def — the shorthand labels for these numbers — in the Dashboard and Value sections of the player pages and the leaderboards, starting immediately. These will be added to the custom dashboard options in the near future. As always, a big thanks to site founder/owner/overlord David Appelman for his hard work, and we hope you find these two new numbers as useful as we do.
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