Library Update: Defense (Def)
One of the great things about FanGraphs is the ever increasing number of stats and features available on the site. One of the downsides of that is that if you miss the initial announcement, things can get awfully confusing awfully quickly. In my efforts to update and expand the FanGraphs Library, I noticed a number of stats that slipped through the cracks and failed to get their own entries after debuting on the site. Today, we are correcting another one of those absences.
One of our most prominently displayed statistics is Defense, or Def if you’re checking out the leaderboards or player pages. We rolled Off and Def out about a year ago as simple combinations of stats we already offered on the site, but if you weren’t hanging out on FanGraphs in mid-September 2013, you might not have known what they meant. Def is simply fielding runs above average (Ultimate Zone Rating at FanGraphs) and the positional adjustment added together and tells you about a player’s total defensive value relative to league average. It is a cumulative stat, so it is based on the quality and quantity of your performance. To learn more about run value stats, check out last week’s entry in the Library.
As always, feel free to contact me on Twitter @NeilWeinberg44, in the comments, or during my weekly chat at 3pm eastern on Wednesdays with any and all FanGraphs and stat related questions.
Neil Weinberg is the Site Educator at FanGraphs and can be found writing enthusiastically about the Detroit Tigers at New English D. Follow and interact with him on Twitter @NeilWeinberg44.
Thanks for these updates, Neil.
Please could you consider adding mouseover text to your leaderboards pages for the column headers (at the very least spelling out the abbreviation; but preferably with a link to the library).
This is a good idea, I’ll pass it along. This happens on the player pages, but not the leaderboards. I don’t know if there’s a reason for it or if it’s just a matter of having the time to code it in.
Yes, that would be great! Also it would be nice to be able to sort by player names… it currently doesn’t sort right… in fact I have no idea what the order it puts them in is when you click Name… I would like to see it sort by last name then first (if they are seperate in the database of course)
Catchers don’t have UZR, what is being used instead?
rSB (stolen base runs from BIS) and RPP (the pitch blocking metric)
Hey Neil,
Can you explain how Def at the team level is calculated? The AL has the DH, so adding up individual player DEF scores results in all AL teams getting a huge penalty.
The first chart of Team DEF is very different than the following chart of Team DEF(which is just the aggregate of the team DEF’s added up – penalizing the AL for the DH). The first chart doesn’t seem to penalize for the DH whereas the second one does.
http://www.fangraphs.com/leaders.aspx?pos=all&stats=fld&lg=all&qual=0&type=1&season=2015&month=0&season1=2015&ind=0&team=0,ts&rost=0&age=0&filter=&players=0&sort=23,d
http://www.fangraphs.com/leaders.aspx?pos=all&stats=bat&lg=all&qual=0&type=6&season=2015&month=0&season1=2015&ind=0&team=0,ts&rost=0&age=0&filter=&players=0&sort=7,d
You have it right. The first page is the fielding tab, so you’re only looking at performance while in the field. This excludes DH’s. The second page is the batting tab, so DH and their negative DEF score is included. Essentially, on the second page, you can look at the “fielding” column of you want to compare team defense without clicking over. Positional adjustment doesn’t matter at the team level because every team has to field all the positions.