Wednesday, May 12, 2010

Jon Loomer drops in to talk about XRBI

This is a guest post by Jon Loomer. Jon is a lifelong Milwaukee Brewers fan who grew up on baseball cards and statistics. He started playing fantasy baseball in the mid-90s, leading him to writing gigs with Rotoworld, TalentedMrRoto, and several other fantasy sports sites. For three seasons, from 2005-2008, Jon also oversaw all fantasy games development, content management, marketing and promotions for the National Basketball Association. Jon has since "retired" from fantasy sports and is currently VP of Strategic Marketing in the non-profit world. You can follow his baseball rantings on his blog at or on Twitter @JonLoomer.

 Last week, I wrote an entry on my blog about the Death and Resurrection of the RBI. Although the Run Batted In is a statistic the mainstream sports media embraces and uses as a pillar to evaluate talent, the Sabermetrics opposition is growing.
I encourage you to read my entire argument, but here it is in summary:
  • RBI heavily influenced by position in lineup;
  • RBI heavily influenced by on base and base running ability of teammates.
 While we are conditioned to think that a singles hitter cannot drive in the runs of a power hitter, the truth is that, given equal opportunities with runners in scoring position, a high volume of singles can indeed result in more runs batted in.

 Though I see the RBI in its current form as largely worthless, I do believe an adjusted statistic would have value. Inspired by the research of Tom Tango, I assigned an RBI value for all singles, doubles, triples, home runs, walks/hit by pitch, and non strikeouts. The result was a way to compare the run production of players across different lineup positions, different teams and different eras.

 I provided a top 100 based on this new stat, which I referred to as XRBI. The top XRBI producers brought few surprises, but it was further down that list that we discovered players like Pete Rose, Lou Brock, Paul Molitor and Rickey Henderson benefitting from this new stat. While the system is not perfect (it values all singles equally and does not account for "clutch" or the absence of "clutch"), I'd contend that it is certainly better than the current, widely accepted iteration.

 Influence of Lineup Spot on Production
Today, I'm going to dive deeper into the RBI disparities in lineup spot. There are natural differences in lineup spot that will give one spot more opportunities than another with runners in scoring position. The obvious example is leadoff. If a batter is to come to the plate four times per game, one of four for the leadoff man is guaranteed to be with the bases empty. As a result, such a player is at a built-in disadvantage to drive in runs.

 When determining XRBI, the value I gave for each single was an average of the value for lineup spots one through nine, with and without the DH. So, you never really got to see just how advantageous lineup spot is.

 But Tom Tango, when developing his wOBA stat, assigned a more granular value. You can see the results here. I again average the values for DH with non-DH because of the difficulties of dealing with players who played in multiple leagues, with and without the Designated Hitter. I also want to assign a universal value to make it much easier to compare players.

 My guinea pig last week was Tony Perez, a Hall of Fame slugger most famous for his play on the 1970s Cincinnati Reds. In 61% of his career plate appearances, Perez hit clean-up or fifth in the lineup. So what might his RBI totals have looked like had he batted elsewhere in the lineup? Below are the RBI he might have collected for each offensive outcome in addition to a total at the far right.

So Tony Perez would have collected 472 fewer RBI (71%) had he batted leadoff his entire career instead of clean-up. That is quite the disparity. Also interesting that there is virtually no difference between the sixth, seventh, eighth and ninth positions in the lineup. The disparities are greatest from one through five.

 If you're sharp, you'll note that Perez actually collected 1,652 total RBI over the course of his career, 33 more than the calculation above had he played his entire career as the clean-up man. Since he only hit there 54% of his career plate appearances, how is this possible?

 Well, you'll note that there is yet another influential factor that determines runs batted in: ability of teammates to get on base. From 1968 through 1977, the Reds finished first or second in the National League in On Base Percentage eight times. There were regularly runners on base and in scoring position when Tony Perez came to the plate. Perez performed well in these situations, but he certainly benefitted from playing with gifted teammates.

 As indicated in the original blog entry, the intent is not to belittle the accomplishments of Tony Perez. Instead, I hope that when people speak of his greatness they will use a statistic other than RBI as the measuring stick.
What other players do you believe benefitted from their position in the lineup? In other words, what players who were regularly seen as run producers significantly benefitted from lineup slot and teammates around them? What players who were not seen as run producers could have been had they been given the opportunity?


  1. Fascinating topic, have you thought about applying the same concept to say Rickey Henderson and runs scored?

  2. Thanks, Mel, and yes. Actually, my intent was to create an adjusted Runs statistic. Haven't figured out the best way to do it. Yet...

  3. RBIs are still a good stat. Scoring runs is the whole point of the game and some guys are just better at knocking them in.

  4. Statwarrior -- Is the player with more RBI still "better at knocking them in" than the player with a far better rate of success but fewer opportunities?

  5. I must digg your post so other folks can look at it, very helpful, I had a tough time finding the results searching on the web, thanks.

    - Norman